SIR.S.M.TAHIR Mob: 9557076999 VMCC SAMPLE QUESTION PAPER (1) CHEMISTRY Time : 3 Hrs Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. State the term ‘order of reaction’ for chemical reactions 2. Which has a higher enthalpy of adsorption, physisorption or chemisorption ? 3. Explain, why does the atomic radii increases considerably from N to P but very little increase is observed from As to Bi. 4. Why does 03 act as a powerful oxidizing agent ? 5. Why is the coordination number of each type of ions in rock salt type crystal structure ? 6. Arrange the following in increasing order of basic strength NH2 , NMe2 , (C2H5)2 NH and (CH3 NH2) 7. Write the IUPAC name of the following compound CH3COCH2COCH3 8. Name the sugars which are present in RNA and DNA. Section – B 9. Write the name of each of the following complex compounds. (i) [Co(NH3)4 (H2O)2]Cl3 10. (ii) [Pt(NH3)4] [NiCl4] Give reason for the following: copper is conducting material while CuSO 4 is conducting only in molten state or in aqueous solutions. 11. The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is 1500 . What is the cell constant, if the conductivity of 0.001 M KCl solution at 298 K is 0.146 10-3 S cm-1 ? 12. Explain the following properties giving suitable examples. 13. A reaction is of second order with respect to a reactant. How will the rate of reaction be affected, if the concentration of this reactant is (i) Ferromagnetism (i) doubled ? (ii) Ferrimagnetism (ii) reduced to half ? Or Why does the rate of any reaction generally decreases during the course of the reaction ? 14. Account for the following observations. (i) Aniline has more pKb value than that for methylamine. (ii) When methylamine solution in water reacts with ferric chloride solution, it gives a precipitate of ferric hydroxide. 15. Which one in the following pairs of substances undergoes SN2 substitution reaction faster and why ? (i) CH2Cl or Cl (ii) Cl or I SIR.S.M.TAHIR Mob: 9557076999 16. SAMPLE QUESTION PAPER (1) VMCC CHEMISTRY A reaction of first order in reactant A and of second order in reactant B. How much is the rate of this reaction affected when (i) the concentration of B is increased to three times (ii) the concentrations of A as well as B are doubled ? 17. Why is it difficult to prepare pure amines by ammonolysis of alkyl halides ? Give reason. 18. How are the following conversions carried out ? (i) Benzyl chloride to benzyl alcohol (ii) Methyl magnesium bromide to 2-methylpropan-2-ol Section – C 19. Raju and his father went to a shop to purchase a battery for their inverter. Shopkeeper showed them two types of batteries, one with lead plates and the other with cadmium plates. The battery with lead plates was cheaper than the battery with cadmium plates. Raju’s father wanted to purchase lead battery as it was cheaper. After reading the above passage, answer the following questions. 20. (i) As a student of chemistry, which battery would you suggest to Raju’s father to buy ? (ii) Why would you suggest to Raju’s father to buy this battery ? Give two reasons. (iii) What are the values associated with the above decision ? Define the following substances. Give one example of each. (i) Antacid 21. (ii) Non-ionic detergents (iii) Antiseptics Write the difference between multimolecular and macromolecular colloids ? Give one example of each. How are associated colloids different from these two types of colloids ? 22. Explain in brief the basic principles of the following metallurgical operations. (i) Zone refining (ii) Vapour phase refining 23. What are nucleosides and nucleotides ? 24. Account for the following observations. (iii) Electrolytic refining (i) NH3 is a stronger base than PH3. (ii) Sulphur has a greater tendency for catenation than oxygen. (iii) Bond dissociation energy of F2 is less than that of Cl2. 25. Compare the low density polythene (LDP) with high density polythene (HDP). 26. Complete the following chemical equations. (i) Ca3P2(s) + H2O (l) (ii) Cu2+ (aq) + NH3(aq) (iii) F2(g) + H2O(l) Or Give reasons for the following. 27. (i) ICl is more reactive than I2. (ii) Neon is used in illuminating warning signal. (iii) Noble gases have very low melting and boiling points. Write the name of the reagents which are used in the following conversions. (i) A primary alcohol to an aldehyde (ii) Butan-2-one to butan-2-ol (iii) Phenol to 2, 4, 6-tribromophenol SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (1) VMCC CHEMISTRY Section – D 28. (i) Account for the following observations. (a) Aldehydes are more reactive than ketone towards nucleophiles. (b) The aldehydes and ketones have lower boiling points than the corresponding acids. (c) The aldehydes and ketones undergo a number of addition reactions. (ii) Give chemical tests to distinguish between (a) acetaldehyde and benzaldehyde (b) propanone and propanol Or Predict the product when cyclohexane carbaldehyde reacts with following reagents. 29. (i) C6H5MgBr followed by H3O+ (ii) Tollen’s reagent (iii) Semicarbazide in the weakly acidic medium. (iv) Excess of ethanol in the presence of acid. (v) Zinc amalgam and dilute hydrochloric acid . (i) Explain the general trends in the following properties of the first series of the transition elements. (a) Stability of + 2 oxidation state (b) Formation of oxometal ions (ii) Assign reasons for each of the following observations. (a) Transition elements exhibit variable oxidation states. (b) Transition metal ions are usually coloured Or Give reasons. 30. (i) Iron is a transition metal while sodium is not. (ii) Cu2+ salts are white. (iii) Zn, Cd and Hg are quite soft and have low melting points. (iv) La(OH)3 is more basic than Lu(OH)3. (v) Third ionization enthalpy of manganese is exceptionally high. (i) State Raoult’s Law for solutions of volatile liquids. (ii) Taking suitable examples, explain the meaning of positive and negative deviations from Raoult’s law. (iv) Calculate the boiling point one molar aqueous solution (density = 1.04 g mL -1) of potassium chloride (Kb = 0.52 K kg mol-1) Or (i) Why is freezing point depression of 0.1 M NaCl solution is nearly twice that of 0.1 M C6H12O6 solution ? (ii) A 0.561 m solution unknown electrolyte depresses the freezing point of water by 2.930C. What is the van’t Hoff factor for this electrolyte ? The freezing point depression constant (K f) for water is 1.860C Kgmol-1 ? SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (2) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. What is Tyndall effect ? 2. A cubic solid is made up of two elements X and Y. Atoms Y are at the corners of the cube and x at the body centre. What is the formula of the compound ? 3. Give the structure of 3-oxopentanal. 4. Under which situations, can an amorphous substance change to crystalline form ? 5. What is ‘rate of a reaction’? 6. Cellulose in our diet is not nourishing. Give reason. 7. Write the IUPAC name of the following compound 8. H3C – CH – CH2 – CH – CH – CH2OH | | | CH3 OH CH3 Why is Co a stronger ligand than Cl- ? Section – B 9. 10. 11. Which compounds of the following couples will react faster in SN2 displacement and why ? (i) 1-bromopentane or 2-bromopentane (ii) 1-bromo-2-methylbutane or 2-bromo-2-methylbutane (i) Explain in brief, why is an alkylamine more basic than ammonia ? (ii) Give a chemical test to distinguish between ethyl-amine and aniline. Explain, why haloarenes are much less reactive than haloalkanes towards nucleophilic substitution reactions ? 12. The decomposition of NH3 on platinum surface, 2NH3, (g) Pt N2(g) + 3H2(g) is a zero order reaction with k = 2.5 10-4 Ms-1. What are the rates of production of N2 and H2 ? or 14 The half-life for radioactive decay of C is 5730 yr. An archaeological artifact contained wood that had only 80 % of the 14C found in living tree. Estimate the age of the sample. 13. The rate constant for a reaction of zero order in A is 0.0030 mol L -1s-1. How long will it take for the initial concentration of A to fall from 0.10 M to 0.075 M ? 14. Name the following coordination compounds, according to IUPAC system of nomenclature. (en = ethane-1, 2 diamine) (i) 15. [Co(NH3)4 (H2O)Cl]Cl2 (ii) [CrCl2(en)2]Cl, Define molar conductivity. Describe how for weak and strong electrolytes, molar conductivity change with concentration solute. 16. Describe the following reactions. (i) Hoffmann’s bromamide reaction (ii) Gattermann reaction SIR.S.M.TAHIR Mob: 9557076999 17. VMCC CHEMISTRY Complete the following chemical equations. (i) 18. (2) SAMPLE QUESTION PAPER P4 + NaOH + H2O (ii) I- + H2O +O3 -3 If the density of NaCl crystal 2.165 g cm , calculate the distance between Na+ and Cl- ions in NaCl crystal. [Molar mass of NaCl = 58.5 g mol-1, NA = 6.02 1023 mol-1] Section – C 19. Draw the structures of white phosphorus and red phosphorus. Which one of these two types of phosphorus is more reactive and why ? 20. Explain what is meant by (i) 21. (ii) A glycosidic linkage (iii) Denaturation ? (iii) H3PO2 Draw the structures of the following molecules. (i) 22. A peptide linkage XeF4 (ii) BrF3 How are the following colloids different from each other with respect to dispersion medium and dispersed phase ? Give one example of each type. (i) 23. An aerosol (ii) A hydrosol (iii) An emulsion Describe the role of (i) NaCN in the extraction of gold from gold one (ii) SiO2 in the extraction of copper from copper matte. (iii) Iodine in the refining of zirconium. Write chemical equation for the involved reaction 24. Explain the following with one suitable example, for each case (i) 25. Cationic detergents (ii) Food preservatives (iii) Analgesics Calculate the emf of the cell in which the reaction is Mg(s) + 2Ag (aq) Mg2+ (aq) + 2Ag(s) + When, [Mg2+] = 0.130 M and [Ag+] = 1.0 10-4 M Given, = - 2.37 V and = + 0.80 Or (i) The resistance of 0.02 M KCl solution in a conductivity cell was found to be 1100. The conductivity of this solution is 4.5 10-3 S cm-1. Calculate the cell constant. 26. (ii) What are the unit of molar conductivity ? (iii) Write Nernst equation for the following cell Mg(s) | || | Cu(s) Miss Rita was asked to synthesized alcohol by acidic hydration of 1-butene. She was unaware of the fact that the vessel she used had some coating of a metal and in addition to alcohol (b.p. 373 K), compound X (b.p. 353 K) was also isolated. X form bisulphate compound as well as 2, 4-dinitrophenyl hydrazone. Separation of alcohol could be made by physical as well as chemical methods. Answer the following questions, based on above passage. 27. (i) How are alcohol and X formed ? (ii) Can alcohol and X give iodoform test ? (iii) Give different methods separation ? (iv) What values are associated with Miss Rita ? Draw the structure of the monomer of each of the following polymers. (i) Polyvinyl chloride (PVC) (ii) Nylon – 6 (iii) Polythene SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (2) VMCC CHEMISTRY Section – D 28. (i) Give chemical tests to distinguish between the following pairs of compounds. (a) (ii) Ethanal and propanal (b) Phenol and benzoic acid Give a plausible explanation for each of the following. (a) There are two – NH2 groups in semicarbazide. However, only one such group is involved in the formation of semicarbazones. (b) Cyclohexanone form cyanohydrins in good yield but 2,2,6-trimethyl cyclohexanone does not. Or An organic compound (A) with molecular formula, C8H8O forms orang-red precipitate with 2, 4,-DNPH reagent and gives yellow precipitate on heating with iodine in the presence of NaOH. It neither reduces Tollen’s or Fehling reagent, nor decolourises bromine water or Baeyer’s reagent. On drastic oxidation with chromic acid, it gives a carboxylic acid (B) having molecular formula , C 7H6O2. Identify the compound (A) and (B) and explain the reactions involved. 29. (i) A solution which is prepared by dissolving 1.25 g of oil of winter green (methyl salicylate) in 99.0 g of benzene has a boiling point of 80.310C. Find the molar mass of this compound. (b.p. of pure benzene = 90.100C and Kb for benzene = 2.530 C kg mol-1). (ii) Calculate the freezing point depression expected for 0.0711 m aqueous solution of Na2SO4. If this solution actually freezes at – 0.320C, then find the value of van’t Hoff factor ? (K f for water is 1.860C kg mol-1) Or (i) The vapour pressure of water is 12.3 kPa at 300 K. Calculate vapour pressure of 1 molal solution of a non-volatile solute in it. (ii) Calculate the mass of a non-volatile solute (molar mass = 40 g mol-1) which should be dissolved in 14 g octane to reduce its vapour pressure to 80%. 30. Account for the following. (i) Transition elements show highest oxidation state in their oxides than fluorides. (ii) Cu has positive electrode potential in the first transition series. (iii) Ionisation enthalpy of lanthanides is lower than actinides. (iv) Potassium dichromate is a good oxidizing agent in acidic medium. (v) Actinides show more number of oxidation states than lanthanides. Or (i) Compare non-transition and transition elements on the basis of their (a) variability of oxidation states. (b) stability of oxidation states. (ii) Give chemical reaction for the following observations. (a) Potassium permanganate is a good oxidizing agent in basic medium. (b) Interconvertibility of chromate ion and dichromate ion in aqueous solution depends upon pH of the solutions. (c) Potassium permanganate is thermally unstable at 513 K. SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (3) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Name the products of hydrolysis of sucrose. 2. Bi (v) is a stronger oxidizing agent than Sb (v) . Explain. 3. What happens when a freshly prepared Fe(OH)3 is shaken with a little amount of dilute solution of FeCl 3? 4. What are the factors which affect the rate of a reaction ? 5. What happen when H3PO2 is heated ? 6. Arrange the following compounds in an increasing order of their acid strengths. (CH3)2CHCOOH, CH3CH2CH(Br) COOH, CH3CH (Br) CH2COOH 7. Give the IUPAC name of the following compound. OH | H3C – CH – CH – CH – CH – CH2OH 8. | | | CH3 OH CH3 What is ligand ? Section – B 9. Describe the Hoffmann’s bromamide reaction with example. Or State reason for the following 10. (i) Ethylamine is soluble in water whereas aniline is not soluble in water. (ii) Boiling points of primary amines are higher than the tertiary amines. What is semiconductor ? Describe the two main types of semiconductors and explain mechanisms for their conduction. 11. List two main difference between order of a reaction and molecularity of a reaction. 12. The rate of a reaction becomes four times when the temperature changes from 300 K to 320 K. Calculate the energy of activation of the reaction, assuming that it does not change with temperature. 13. 14. Rearrange the compounds as directed. (i) In an increasing order of basic strength. C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2 (ii) In a decreasing order of basic strength. Aniline, p-nitroaniline and p-toluidine For the complex [Fe (en)2Cl2] Cl, (en = ethylenediamine), identify (i) The oxidation number of iron, (ii) The hybrid orbitals and the shape of the complex, (iii) The magnetic behavior of the complex. (iv) Name of the complex. (at. No. Fe = 26) SIR.S.M.TAHIR Mob: 9557076999 15. (3) VMCC SAMPLE QUESTION PAPER CHEMISTRY Explain each of the following with a suitable example. (i) Piezoelectric effect (ii) Frenkel defect in crystals 16. What happens when iodoform is heated with silver powder ? Write a chemical reaction. 17. Complete the following reaction equations. (i) (ii) 18. C6H5N2Cl + KI C=C + Br2 … CCl4 Formulate the galvanic cell in which the following reaction takes place. Zn(s) + 2Ag+ (aq) Zn+ (aq) + 2Ag(s) State (i) Which electrode is negatively charged ? (ii) The reactions taking place at each of its electrode. (iii) What are the carries of current within this cell ? Section – C 19. 20. 21. (i) Give a chemical test to distinguish between ethanol and phenol. (ii) Write a Kolbe’s reaction with an example. (i) Why does soap not work in hard water ? (ii) How do antiseptics differ from disinfectants ? (iv) Give one use of ranitidine, Humans, monkeys and guinea pigs do not have the enzymes necessary for the biosynthesis of vitamin C, so they must include the vitamin in their diets. It is also required for the synthesis of collage, which is the structural protein of skin, tendors, connective tissue and bone. Answer the following questions based on above passage. 22. 23. (i) Write structure of vitamin C and the functional groups therein. (ii) Is it acidic in nature ? What is the common name of vitamin C ? (iii) What values do you get from the above passage ? What would be observed when (i) an electric current is passed through the sol ? (ii) a beam of light is passed through sol ? (iii) an emulsion is subjected to high speed centrifugation ? Write the structure of the following species, (i) (ii) H2S2O7 (iii) HOClO2 ? 24. A reaction with rGo < 0, always has an equilibrium constant value greater than 1. Prove it. 25. Write balanced chemical equations for the following reactions. 26. (i) Aluminium dissolves in aqueous hydrochloric acid. (ii) Tin react with a hot alkali solution. (iii) Heating of white phosphorus with conc. NaOH solution in an inert gas atmosphere. Write the names and structures of the monomers of the following polymers. (i) Buns – S (ii) Neoprene (iii) Nylon-6, 6 Or Give examples of natural, semi-synthetic and synthetic polymers. SIR.S.M.TAHIR Mob: 9557076999 27. SAMPLE QUESTION PAPER (3) VMCC CHEMISTRY State the principles which serve as basis for the following operations in metallurgy. (i) Froth floatation process (ii) Magnetic separation (iii) Refining by liquation Section – D 28. (i) Define the term osmotic pressure. How the molecular mass of a substance can be determined by a method based on measurement of osmotic pressure ? (ii) Find the temperature at which solution containing 24 g of glucose, (C6H12O6) in 250 g of water freeze. (Kf for water = 1.86 K kg mol-1) [Ans. Water will freeze at 270.768 K] Or A solution containing 30 g of non-volatile solute exactly in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. 18 q of water is then added to the solution and the new vapour pressure becomes 2.9 kPa at 298 K. Calculate. 29. (i) Molar mass of the solute and (ii) Vapour pressure of water at 298 K [Ans. (i) 23 g mol-1, (ii) 3.53 kPa] Convert the following. (i) Ethyl benzene to benzoic acid (ii) Toluene to benzaldehyde (iii) Ethanal to butan-1, 3diol (iv) Ethanal to but-2-enal (v) Ethanal to but-2-enoic acid Or Draw the structures of the following compounds. 30. (i) 3-methyl butanal (ii) p-nitropropiophenone (iii) p-methylbenzaldehyde (iv) 4-methylpent-3-en-2-one (v) 4-chloropentan-2-one (i) What may be the possible oxidation states of the transition metals with following d-electronic configurations in the ground state of their atoms. 3d3 4s2, 3d5 4s2 and 3d6 4s2 Also indicate the relative stability of the oxidation states in each case. (ii) The chemistry of actinoids is more complicated than lanthanoids. Why ? (iii) What are the consequences of lanthanoid contraction ? (iv) Lanthanum and lutetium do not show colouration in solutions. Or Give reasons for the following observations (i) The atomization enthalpies of transition elements are high. (ii) The transition metals and many of their compounds acts as good catalyst. (iii) From element of element, the lanthanoid contraction. (iv) The E0 value of the Mn3+/Mn2+ couple is more positive than that for Cr3+/Cu2+. (v) Scandium (Z = 21) does not exhibit variable oxidation states yet it is regarded as transition element. SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (4) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Define activation energy. 2. What is meant by chemisorptions ? 3. Complete the following equation. Cu + HNO3 (dilute) 4. Why is NO stronger ligand than Cl- ? 5. How is that alcohol and water are miscible in all proportions ? 6. Name the purines present in DNA. 7. Write the IUPAC name of the following. CH3 H H 8. H H Br Give simple tests to distinguish between the following pair of compounds : Pentan-2-one and pentan-3-one. Section – B 9. Calculate the packing efficiency of a metal crystal for a simple cubic lattice. 10. Explain the following terms with one suitable example of each. 11. (i) Electrical properties of solid (ii) Paramagnetism Calculate the emf for the given cell at 250C Cr|Cr3+ (0.1 M) || Fe2+ (0.01) M| Fe [Given, = - 0.74 V, = 0.44 V] [Ans. EMF = + 0.2606 V] Or Explain with examples the term weak and strong electrolytes. 12. What are pseudo first order reactions ? Give one example of such reaction. 13. Explain the terms. 14. (i) Elementary step in a reactions. (ii) Rate determining step of a reaction. Draw the structure of (i) hypochlorous acid (ii) chlorous acid SIR.S.M.TAHIR Mob: 9557076999 15. 16. (i) Oxygen is gas but sulphur is a solid. (ii) The halogens are coloured CHEMISTRY Describe the shape and magnetic behavior of the following complexes. [Co(NH3)6]3+ (ii) [Ni(CN)4]2- How will you convert (i) 18. VMCC Explain the following observations (i) 17. (4) SAMPLE QUESTION PAPER nitrobenzene to aniline ? (ii) aniline to iodobenzene ? Write equation for (i) Sandmeyer’s reaction (iii) Coupling reaction Section – C 19. A solution of CuSO4 is electrolysed for 16 min with a current of 1.5 A. What is the mass of copper deposited at the cathode ? 20. [Ans. Copper deposited at cathode = 0.473 g] Differentiate among a homogeneous solution, a suspension and colloidal solution. Give suitable example of each. 21. Describe how the following changes are brought about ? (i) Pig iron into steel (ii) Zinc oxide to metallic zinc (iii) Impure titanium into pure titanium Or Dr. Saxena, head of metallurgical division always insisted for refining of copper by electrolytic method, instead of other convenient methods, though it is power consuming and takes longer time. Based on the passage, answer the following questions 22. 23. (i) Is electrolytic refining environmental friendly or economical ? (ii) What is cathode, anode and electrolytic solution ? (iii) Write the values shown by Dr. Saxena. (i) What prompted Bartlett to the discovered of noble gas compounds ? (ii) State two important uses of noble gases. (i) Write the mechanism of the following reaction. n-BuBr + CN (iii) 24. 25. Why is the dipole moment of chlorobenzene lower than that of cyclohexylchloride ? (i) Benzoquinone from phenol (ii) 30-alcohol from methyl magnesium bromide (iii) Propan-2-ol from propene Define the following as related to proteins. Polypeptides (ii) Primary structure (iii) Fibrous proteins (iii) Polythene Write chemical equation for the synthesis of (i) 27. m-BuCN How would you obtained the following ? (i) 26. EtOH, H2O Nylon -6 (iii) Nylon-6,6 There is growing interest in the use of chelate therapy is medicinal chemistry. An example is the treatment of problems caused by the presence of metals in toxic proportions in plant/animal systems. Detection of cations through coloured complex formation is done in qualitative analysis. Read the above passage and answer the followed questions. Read the above passage and answer the following questions. SIR.S.M.TAHIR Mob: 9557076999 (4) SAMPLE QUESTION PAPER VMCC CHEMISTRY (i) Name the chelating agent that can remove copper, iron and lead from water. (ii) Name the compound that inhibits the growth of tumours (iii) Recent studies show that cis-platin can cause serious effects; including server kidney damage. What is the alternative medicine ? (iv) What values do you get form passage ? Section – D 28. (i) Calculate the molarity and molality of 15 % solution (by weight) of sulphuric acid of density 1.020 g cm-3. (Atomic masses of H = 1,0 = 16, S = 32 u) [Ans. (i) Molarity = 156 M, Molality = 1.08 M] (ii) Explain why a solution of chloroform and acetone shows negative deviation from Raoult’s law ? Or (i) Henry’s law constant for CO2 dissolving in water is 1.67 108 Pa at 298 K. Calculate the quantity of CO2 in 1 L of soda water when packed under 2.5 atm CO 2 pressure at 298 K. [Ans. (ii) = 3707 g] Define the term ‘molarity’ of a solution. State one disadvantage in using the molarity as the unit of concentration. 29. (i) Complete the following chemical reaction equations. (a) Fe2+ (aq) + (b) Cr2 (ii) (aq) + H+ (aq) (aq) + I- (aq) + H+ (aq) Explain the following observations. (a) Transition elements are known to form many interstitial compounds. (b) With the same d4, d-orbital configuration Cr2+ ion is reducing while Mn3+ ion is oxidizing. (c) Cu+ ion is unstable in aqueous solutions Or (i) Complete the following chemical eqations (a) Cr2 (aq) + H2S(g) + H+ (aq) 2+ (b) Cu (aq) + I-(aq) (ii) How would you account for the following ? (a) The oxidizing power of oxoanions are in the order V < Cr2 < Mn (b) First ionization enthalpy of Cr is lower than that of Zn. (c) Cr2+ is a strong reducing agent than Fe2+ 30. (i) How will you prepare the following compounds starting with benzene ? (a) Benzaldehyde (ii) (b) Acetophenone How will you bring about the following conversions ? (a) Propanone to propene (b) Ethanol to 3-hydroxy butanal (c) Benzaldehyde to benzophenone. An organic compound A on treatment with acetic acid in the presence of sulphuric acid produces an ester B. A on mild oxidation gives C. C with 50 % KOH followed by acidification with dil. HCl generates A and D. D with PCl5 followed by reaction with ammonia gives E. E on dehydration produces hydrocyanic acid. Identify the compound, A, B, C, D and E. SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (5) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Identify the reaction order from the following rate constant k = 2.3 10-5 L mol-1 s-1 [Ans. Second order] 2. Why is adsorption always exothermic ? 3. What is the basicity of H3PO2 and why ? 4. Give an example of linkage isomerism. 5. Write the structure of 2-(2-chlorophenyl)-1-iodoocatane. 6. Write Reimer-Tiemann reaction giving an example. 7. Write IUPAC name of (CH3)3CCH2COOH. 8. What are -amino acids ? Section – B 9. How are the following properties of crystals affected by Schottky and Frenkel defects ? (i) Density (ii) Electrical conductivity 10. What is meant by ‘doping’ in a semiconductor ? 11. (i) Express the relation between conductivity and molar conductivity of a solution held in a cell. (ii) What is meant by limiting molar conductivity ? 12. Is there any reaction for which reaction rate does not decrease with time ? 13. A reaction is of second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to one fourth ? What is the units of rate constant for such a reaction ? 14. 15. [Ans. ¼ (one fourth] (i) Draw the structure of XeF6 (ii) Does the hydrolysis of XeF6 leads to a redox reactions ? Give reason Bleaching of flowers by Cl2 is permanent while by SO2 is temporary ? 16. Using the valence bond theory, predict the geometry and magnetic behavior of [CoF6]3(At. No. of Co = 27) Or Explain the following terms 17. (i) Crystal field splitting in an octahedral field (ii) Spectrochemical series Write equations for (i) 18. Diazotisation reaction (ii) Acetylation reaction Assign reason for (i) Amines are less acidic than alcohols of comparable molecular masses. SIR.S.M.TAHIR Mob: 9557076999 (ii) SAMPLE QUESTION PAPER (5) VMCC CHEMISTRY Aliphatic amines are stronger bases than aromatic amines. Section – C 19. A voltaic cell is set up at 2500 C with the following half cells. Ag+ (0.001 M) | Ag and Cu2+ (0.10 M) | Cu What would be the voltage of this cell ? ( [Ans. 20. = 0.46 V) = 0.1225 V] What is an adsorption isotherm ? Describe Freundlich adsorption isotherm. Or Write three distinctive features of chemisorptions which are not found in physisorption. 21. 22. 23. Describe the role of the following (i) NaCN in the extraction of silver from a silver ore. (ii) Iodine in the refining of titanium. (iii) Cryolite in the metallurgy of aluminium. Explain each of the following (i) Nitrogen is much less reactive than phosphorus. (ii) The stability of +5 oxidation state decreases down the group 15. (iii) The bond angles (O-N-O) are not of the same value in and How would you differentiate between SN1 and SN2 mechanism of substitution reactions ? Give one example of each. 24. (i) Describe the mechanism of hydration of ethane to yield ethanol. (ii) Write the structure and IUPAC names of the major product expected from the catalytic reduction of butanal ? 25. Haemoglobin, the red pigment of blood, which acts as oxygen carrier is a coordination compound. The deficiency of iron leads to anaemia. Vitamins are also essential for the growth of our body. Vitamin B 12 deficiency leads to pernicious anaemia. 26. (i) Name the complex present in vitamin B 12. Which metal is present in it ? (ii) What are the sources of iron in our diet ? (iii) What are the values possessed by people taking iron rich diet ? Write chemical equations for the synthesis of (i) 27. Terylene (ii) Neoprene (iii) Teflon (iii) Antacids Describe the following giving one example for each. (i) Detergents (ii) Artificial sweetener Section – D 28. (i) Define mole fraction. (ii) What is meant by molality of the solution ? (iii) Calculate the amount of KCl which must be added to 1 kg of water so that the freezing point is depressed by 2K. (Kf for water = 1.86 K kg mol-1). [Ans. (iii) Amount of KCl = 40.05 g] SIR.S.M.TAHIR Mob: 9557076999 (5) SAMPLE QUESTION PAPER VMCC CHEMISTRY Or What is van’t Hoff factor ? What possible values can it have if the solute molecules undergo (i) dissociation ? (ii) A solution urea in water has a boiling point of 37..128 K. Calculate the freezing point of the same solution. [Given, nor water Kf = 1.86 Km-1, Kb = 0.52 Km-1] [Ans. Freezing point = 272.543 K] 29. (i) Give reasons for the following observations (a) In series Sc to Zn, enthalpy of atomization of Zn is the lowest. (b) Mn (II) ion shows maximum paramagnetic character amongst the bivalent ions of first transition series. (c) Scandium (At. No.21) salts are white. (ii) Describe the reactions involved in the preparation of K2Cr2O7 from chromite ore. Or (i) Give reason for each of the following. (a) Size of trivalent lanthanoid cations decreases with increases in the atomic number . (b) E0 value fo Mn, Ni and Zn are more negative than expected. (c) Ionisation enthalpies of Ce, Pr and Nd are higher than Th, Pa and U. (ii) Write steps involved in the preparation of (a) Na2CrO4 from chromite ore and (b) K2MnO4 from pyrolusite ore 30. Identify A, B, C, D and E in the following sequence of reactions. A Cl2 CHCl3 NaOH B C6H5COCl C C6H5/AlCl D+E Or (a) Identify A, B and C in the following sequence of reactions CH3CHO A Conc. H2SO4 B HBr + Peroxide (b) Predict the structures of products formed when benzaldehyde is treated with (i) Conc. NaOH (ii) HNO3 / H2SO4 (at 273 K – 383 K) C SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (6) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Arrange the following compounds in order of increasing boiling points. Chloropropane, isopropyl chloride, 1-chlorobutane 2. Give the IUPAC name of the following compound (CH 3)2C = CHCOOH. 3. For the reaction, N2(g) + 3H2(g) 2NH3 (g) If [NH3] / t = 4 10 mol L s , what is the value of - [H2]/ t ? -8 [Ans. 4. -1 -1 = 6 10-8 mol L-1 s-1] Which of the following is most effective electrolyte in the coagulation of Fe 2O3 .H2O/Fe3+ sol ? KCl, AlCl3, MgCl3, K4[Fe(CN)6] 5. Which nucleic acid is responsible for protein synthesis in the cell ? 6. Which xenon compound is isostructural with ICl6 ? 7. What happens to the colour of coordination compound [Ti(H2O)6]Cl3 when heated gradually ? 8. Write the structure of phenylisopentylether. Section – B 9. (i) For a weak electrolyte molar conductance in dilute solution increases sharply as its concentration in solution is decreased, give reason. (ii) 10. Write overall cell reaction for lead storage battery when the battery is being charged. Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law with t1/2 = 3h . Calculate the fraction of sucrose which remains after 8 h. [Ans. After 8h fraction of sucrose left = 15.76%] Or The rate constants of a reaction at 500 K and 700 K are 0.02 s-1 and 0.07 s-1 respectively. Calculate value of activation energy for the reaction [Given, R = 8.314 JK-1 mol-1] 11. [Ans. Ea = 1823 kJ] For a chemical reaction, variation in concentration, In [R] (i) What is the order of the reaction ? (ii) What are units of rate constant, k for the reaction ? (iii) If initial concentration of the reactant is half of the original concentration how will t1/2 change ? 12. (iv) Draw the plot of log [R0/[R] vs time(s) (i) Draw the structure of phosphorus acid (H 3PO3). (ii) Write a chemical reaction for its use as reducing agent. In (R) vs time (min) plot is shown below: Time (min) SIR.S.M.TAHIR Mob: 9557076999 13. SAMPLE QUESTION PAPER (i) PH3 has lower boiling point than NH3, Why ? (ii) Complete the following chemical reactions. (6) VMCC CHEMISTRY I2 + conc. HNO3 HgCl2 + PH3 14. (i) Give the electronic configuration of the d-ordibtals of Ti in [Ti(H2O)6]3+ ion and explain why this complex is coloured ? [At. No. of Ti = 22] (ii) Write IUPAC name of [Cr(NH3)3 (H2O)3]Cl3. 15. Show the mechanism of acylation of ethanamine and write the IUPAC name of the product formed. 16. Write a chemical equation for each to represent 17. (i) Schiemann reaction (ii) Carbylamine reaction Sodium crystallizes in a bcc unit cell. Calculate the approximate number of unit cells in 9.2 g of sodium ? [Ans. 1.204 1023] (Atomic mass of Na = 23 u) 18. What is the difference between amorphous solid and crystalline solid ? Section – C 19. (i) Calculate the charge in coloumbs required for oxidation of 2 moles of water to oxygen ? [Given, 1 F = 965000 C mol-1] (ii) Zinc / silver oxide cell is used in hearing aids and electric watches. The following reactions occur: Zn(s) Zn2+ (aq) + weE0 (Zn2+ / Zn) = - 0.76 V Ag2O + H2O + 2e- 2Ag + 2OHEo (Ag+ / Ag) = 0.344 V Calculate (i) Standard potential of the cell (ii) Standard Gibbs energy [Ans. (i) 3.86 105C (ii) 20. 21. = 1.10 V, = -213.072 kJ] Give reason for the following observations. (i) Colloids are stabilized due to Brownian movement. (ii) Cottrell’s smoke precipitator is fitted at the mouth of chimney used in factories. (iii) Colloidal gold is used for intramuscular injection. (i) Extraction of Au by leaching with NaCN involves both oxidation and reduction. Justify by giving equations for the reactions involved. (ii) Why is the froth flotation method selected for the concentration of sulphide ores Or Outline the principle of the method used for refining of 22. (i) Nickel (ii) Zirconium (iii) Tin Write balanced chemical equations for the following reactions (i) Dimeric selenium chloride undergoes disproportionation reaction. (ii) Reaction of gold with aqua-regia. (iii) When phosphine is passed through mercuric chloride solution. SIR.S.M.TAHIR Mob: 9557076999 23. SAMPLE QUESTION PAPER (6) VMCC CHEMISTRY Account for the following. (i) Chloromethane reacts with KCN to form ethanenitrile as main product and with AgCN to form methyl isocyanide as chief product. (ii) Chloroform should be stored in dark coloured bottles and these bottles should be completely filled. 24. 25. 26. (iii) Benzylic halides show high reactivity towards SN1 reaction. (i) Give one reaction of D-glucose which cannot be explained by its open chain structure. (ii) Give one example each for essential and non-essential amino acids. (iii) Differentiate between keratin and insulin. Identify aliphatic biodegradable polyester which is used in packaging and orthopedic devices. (i) Write its full form (name) (ii) Give the structures of monomers from which it is formed. (iii) Show the formation of polymer. Rohan and Kamlesh are two close friends and roommates also. Rohan has a habit of taking sleeping pills daily at night. Kamlesh advice Rohan not to take sleeping pill regularly without consulting a doctor because it can harm on health. Read the above paragraph and answer the following questions (i) Comment sleeping pills are recommended to patients suffering from sleeplessness but it is not advisable to take them without consulting the doctor. 27. (ii) What value obtained by the above action ? (iii) What are the adverse effect of sleeping pills on human. (i) Give chemical tests to distinguish between : (a) Iso-propyl alcohol and n-propylalcohol (b) Phenol and alcohol (c) Methyl ethanoate and ethyl ethanoate Section – D 28. (i) Menthol is a crystalline substance with peppermint taste. A 6.2 % solution of menthol in cyclohexane freezes at – 1.950C. Determine the formula mass of menthol. The freezing point and molal depression constant of cyclohexane are 6.50C and 20.0 Km-1, respectively. (ii) State Henry’s law and mention its two important applications. (iii) Which of the following has higher boiling point and why ? 0.1 M Na2SO4 or 0.1 M sucrose Or (i) Define azeotropes and explain briefly minimum boiling azeotrope by taking suitable example. (ii) The vapour pressures of pure liquids A and B are 450 mm and 700 mm of Hg respectively at 350 K. Calculate the composition of liquid mixture if total vapour pressure is 600 mm of Hg. Also find the composition of the mixture in vapour phase. [Ans. (i) MB = 158 g mol-1] Or (iii) In liquid phase In vapour phase SIR.S.M.TAHIR Mob: 9557076999 29. (i) (ii) SAMPLE QUESTION PAPER (6) VMCC CHEMISTRY (a) Why copper not replace hydrogen from acids. (b) Cu+ is a d10 ion and colourlens but Cu2O is red and Cu2S is black. Explain. (c) Explain why Ce4+ is a strong oxidizing agent ? Describe the oxidizing property of KMnO 4 in neutral of faintly alkaline medium for its reaction with iodide ions and thiosulphate ions. Or (i) Account for the following (a) Interstitial compound are well known for transition metals. (b) In the first transition series only copper has positive electrode potential. (c) Oxoanions of a metal show higher oxidation state. (ii) Which is the last element in the series of actinoides ? Write the electronic configuration of this element. Comment on the possible oxidation states of this element. 30. (i) An organic compound (A) which has characteristic odour , on treatment with conc. NaOH forms two compounds (B) and (C). Compound (B) has molecular formula C7H8O which on oxidation gives back (A) . The compound (C) is a sodium salt of an acid. When (C) is treated with sodalime it yields an aromatic hydrocarbon (D). Deduce the structures of (A), (B), (C) and (D). Write the sequence of reactions involved. (ii) Arrange the following in the increasing order of the property indicated : (a) Benzoic acid, 4-nitrobenzoic acid, 3, 5-dinitrobenzoic acid, 4-methoxybenzoic acid (acid strength). (b) Acetaldehyde, acetone, diterbutylketone, methyltert-butyl ketone (reactivity towards HCN). Or (i) Complete each synthesis by filling the missing starting materials, reagents or products. (X, Y and Z). (a) C6H5CHO + CH3CH2CHO (ii) NaOH X (b) CH3CH2CH2CH2OH Y CH3CH2CH2COOH (c) CH3(CH2)9COOC2H5 Z CH3(CH2)9 CHO How will you bring about the following conversions in not more than two steps ? (a) Toluene to benzaldehyde (b) Ethylcyanide to 1-phenylpropanone. SIR.S.M.TAHIR Mob: 9557076999 (7) SAMPLE QUESTION PAPER VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Write the product obtained when benzyl phenylether is heated with HI. 2. Gases with high critical temperature are readily adsorbed. Why ? 3. Write the IUPAC name of the compound CH2(Cl)COCH(CH3) CONH2 4. Which of the following compounds has a lone pair of electrons at the central atom ? H2S2O8, H2S2O7, H2SO3, H2SO4 5. What type of linkage holds together the monomers of DNA ? 6. Complete the following reaction, CH3 – CH = CH2 X Y 7. Write a non-exothermic reaction taking place in the blast furnace during extraction of iron. 8. Write the chemical reaction involved in reformatsky reaction. Section – B 9. Write the names associated with the following reactions. (a) RCONH2 + Br2 + 4NaOH + RNH2 + Na2CO3 + 2NaBr + 2H2O (b) Ar CuCn/KCN ArCN + N2 (c) R – NH2 + CHCl3 + 3KOH (d) Ar 10. X- Cu/HCl R – NC + 3KCl + 3H2O Heat ArCl + N2 + 3CuX KF has occp structure. Calculate the ionic radius of F- ion if the side of the cube or edge length is 400 pm. How many F- ions and octahedral voids are there in the unit cell ? 11. 12. (a) Give reason why is Frenkel defect found in AgCl ? (b) What is the difference between phosphorus doped and gallium doped silicon semiconductors ? Describe the construction of a H2 – O2 fuel cell and the reactions taking place in it. Or Define the terms given below. (a) Conductivity (b) Cell constant What are their units ? 13. What is a flux ? What is the rote of flux in the metallurgy of iron and copper ? 14. There is feeling of weakness and discomfort in breathing at high altitude. Explain 15. Give chemical reactions in support of the following observations. (a) Sulphuric acid has low volatility. (b) Iodide ions can be oxidized by oxygen in acidic medium. 16. Propose mechanism of the reaction taking place when (a) (-)2 bromooctane reacts with sodium hydroxide to form (+) octane-2-ol. SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (7) VMCC CHEMISTRY (b) 2-bromopentae is heated with (alc.) KOH to form alkenes. 17. The sum of first and second ionization enthalpies and third and fourth ionization enthalpies of nickel and platinum are IE1 + I2 (kJ mol-1 IE3 + IE4 (kJ mol -1) Ni 2.49 8.80 Pt 2.66 6.70 Based on the above information, answer the following. (a) Which is the most common oxidation state for Ni and Pt ? why ? (b) Out of the two, name the metal which can easily form compounds in + 4 oxidation state and why ? 18. Describe a chemical test in each case to distinguish between the following pairs of compounds (a) Aniline and N-ethylaniline. (b) N-methyl propan-2-amine and N-ethyl-N- methylethanamine. Section – C 19. Among the fuel cells, H2 – O2 fuel cell is most commonly used for providing electrical power in Apollo space propamme. The cell run continuously as long as the reactants are supplied. (a) Write the reactions at cathode and anode. (b) What are the values associated with using fuel cells ? 20. Write (a) Reaction involved in the preparation of a biodegradable polyester. (b) Monomer unit of synthetic rubber (neoprene) (c) One use of Bakelite. 21. (a) Which the Zwitter ion structure of glycine. (b) What is meant by inversion of sugar (c) Name the vitamin in each case whose deficiency causes (i) Night blindness 22. (ii) Poor coagulation of blood Write chemical equations for the following reactions. (a) Oxidation of nitrite ion by Mn in acidic medium. (b) Acidification of potassium chromate solution. (c) Disproportionation of managanese (VI) in acidic solution. (d) Disproportionation of manganese (VI) in acidic solution. Or Account for the following. (a) Europium (II) is more stable cerium (ll) (b) Cobalt (II) is stable in aqueous solution but in the presence of complexing agent , it is easily oxidized. Explain. (c) Actinoides show irregularities in the electronic configuration. 23. Give plausible explanation for each of the following. (a) Ortho-nitrophenol is more acidic than ortho-methoxyphenol. (b) Alcohols are easily protonated in comparison to phenols (c) The relative ease of dehydration of alcohols is tertiary > secondary > primary.. 24. On dissolving 19.5 g of CH2FCOOH in 500 g of water, a depression of 10C in freezing point of water is observed. Calculate the van’t Hoff factor and dissociation constant of fluoroacetic acid. Given, SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER Kf = 1.86 Kg mol-1. 25. (7) VMCC CHEMISTRY [Ans. Van’t Hoff factor I = 1.0753, Dissociation constant = 3.07 10-3] (a) Name one substance which can act as both (i) Analgesic and antipyretic (ii) Antiseptic and disinfectant (b) Explain the following terms with suitable example of each. (i) Broad spectrum antibiotics. (ii) Anionic detergents. 26. 27. (a) Why does physisorption decrease with increase of temperature ? (b) Mention two common properties of sol and emulsions. (c) Differentiate between electrophoresis and electro-osmosis. (a) State the hybridization and magnetic behavior of [Cr(CO)6] (b) What are the various factors affecting crystal field splitting energy ? (c) Which of the two is more stable and why ? K4[Fe(CN)6] or K3[Fe(CN)6] Section – D 28. (a) A white solid A on treating with caustic soda gives a pungent smelling gas B. B on catalytic oxidation forms gas C. C gives brown fumes of gas D, on further oxidation which on dissolving in water forms HNO3 Identify A, B, C, D and give the sequence of reactions involved. (b) Arrange the following in order of property indicated for each set: (i) HCL, HI, HBr, HF – Decreasing thermal stability. (ii) Xe, He, Kr, Rn, Ne – Decreasing order of electron gain enthalpy. Or (a) Give reasons. (i) Solid PCl5 is an ionic compound. (ii) Most of the reactions of fluorine are axothermic (iii) Ozones is thermodynamically unstable. (b) Draw the structures of the following. 29. (i) XeO3 (ii) H4P2O7 (a) A compound A on oxidation B(C2H4O2). A reacts with dil. NaOH and on subsequent heating forms C. C on catalytic hydrogenation gives D. Identify A, B, C, D and write down the reactions involved. (b) Write chemical equations to carry out the following conversions. (i) Benzene to benzylalcohol (ii) Propanenitrile to 1-phenyl-propanone. Or (a) An organic compound X undergoes acid hydrolysis to form two compound Y and Z. Y reacts with sodium carbonate to form A. A is heated with sodalime to form B(CH4). Y on reduction with LialH4 forms Z. Identify X, Y, Z, A, B and write the reactions involved. (b) Account for the following. (i) Benzoic acid does not undergo Friedel-Craft reaction. SIR.S.M.TAHIR Mob: 9557076999 (ii) 30. (a) SAMPLE QUESTION PAPER (7) VMCC CHEMISTRY pKa value of chloroacetic acid is lower than pKa value of acetic acid. For the reaction, C12H22O11 + H2O H+ C6H12O6 + C6H12O6 Write (i) Expression of rate of reaction. (ii) Rate law equation (iii) Molecularity (iv) Order of reaction (v) The following data were obtained during the first order thermal decomposition of SO 2Cl2, at constant volume, SO2Cl2 (g) SO2(g) + Cl2(g) Experiment Time/s Total pressure/atm 1 0 0.5 2 100 0.6 Calculate the rate of reaction when total pressure is 0.65 atm. Or (a) Illustrate graphically the effect of catalyst on activation energy.. (b) Catalysts have no effect on the equilibrium constant. Why ? (c) The decomposition of A into product has value of k as 4.5 103 s-1 at 100C and activation energy is 60 kJ mol-1. Calculate the temperature at which the value of k will be 1.5 104 s.-1 [Ans. (b) Rate = 7.8 10-4 atms-1 (c) Temperature = 240C] SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (8) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. A and B liquids on mixing produce a warm solution. Which type of deviation from Raoult’s law is there ? 2. Why is ferric chloride preferred over potassium chloride in case of a cut leading to bleeding ? 3. Among octahedral and tetrahedral crystal fields, in which case the magnitude of crystal field splitting is larger ? 4. How would you convert ethanol to ethane ? 5. Write two important uses of formalin. 6. Why do amines acts as nucleophiles ? 7. Why can’t aluminium be reduced by carbon ? 8. What are the ultimate products of digestion of proteins ? Section – B 9. Gold (atomic mass = 197 u, atomic radius = 0.144 nm) crystallizes in a face centered unit cell. Determine the density of gold, [NA = 6.022 1023 mol-1] [Ans. Density of gold = 19.35 g cm-3] 10. Classify each of the following as being either a p-type or an n-type semiconductor. Give reasons 11. (i) Si doped with in (ii) Si doped with P Determine the molarity of an antifreeze solution containing 250 g water mixed with 222g ethylene glycol (C2H6O2). The density of this solution is 1.07 g/mL. [Ans. Molarity = 8.12 M} 12. An aqueous solution containing urea was found to having boiling point more than the normal boiling point of water (373.13 K). When the same solution was cooled it was found that its freezing point is less than the normal freezing point of water (273.13 K). Explain these observations. 13. Consider the decomposition of hydrogen peroxide in alkaline medium which is catalysed by iodide ions. OH-/I- 2H2O2 2H2O + O2 This reaction takes place in two steps as given below. 14. Step I H2O2 + I- 2H2O + IO- (slow) Step II H2O2 + IO- H2O + I- + O2 (fast) (i) Write the rate law expression and determine the order of reaction wrt H 2O2 (ii) What is the molecularity of each individual step ? (i) What is the rote of depressant in froth floatation process ? (iii) Out of C and CO which is a better reducing agent for FeO ? (a) In the lower part of blast furnace (Higher temperature) SIR.S.M.TAHIR Mob: 9557076999 (b) In the upper part of blast furnace 15. 16. (8) SAMPLE QUESTION PAPER VMCC CHEMISTRY (Lower temperature) Complete the following reactions. (i) P4 + 8 SOCl2 (ii) I- + O2 + H2O Using valence bond theory, predict the geometry and magnetic character of [Ag(CN) 2](Atomic number of Ni is 28) 17. 18. (i) Write the structure of following compound. 1-bromo-4-sec butyl-2-methylbenzene (ii) How will you bring about the conversion ? Methyl bromide to methyl iodide Explain (i) Grignard reagent should be prepared under anhydrous conditions. (ii) C6H5CHClCH3 is hydrolysed more easily with KOH than C6H5CH2Cl Or Arrange the following compounds in the decreasing order of reactivity towards SN2 displacement reaction and give reasons in support of your answer. (i) C2H5Br, C2H5I, C2H5Cl (ii) (CH3)3CBr, CH3CH2CHBrCH3, CH3CH2CH2CH2Br Section – C 19. Draw the structures of the following. (i) 20. H2S2O8 (ii) XeF2 (iii) XeOF4 In a hydrolysis reaction, 5g ethyl acetate is hydrolysed in presence of dilute HCl in 300 min. If the reaction is of first order and the initial concentration of ethyl acetate is 22g/L , calculate the rate constant of the reaction. [Ans. K = 8.6 10-4 s-1] 21. (i) Give reasons for the following. (a) Glucose does not give 2, 4-DNP test and Schiff’s test. (b) Amino acids have high melting points and are soluble in water. 22. (ii) What is meant by the secondary structure of proteins ? (i) Give an example of a synthetic rubber and mention its main advantage. (a) Glucose does not give 2,4-DNP test ad Schiff’s test. (b) Amino acids have high melting points and are soluble in water. (ii) What is mean by the secondary structure of proteins ? (iii) Arrange the following polymers in the increasing order of tensile strength. Nyclon-6, Buna-S, Polythene 23. Give one example for each of the following (i) An artificial sweetner whose use is limited to cold drink. (ii) A non-ionic detergent (iii) A pain reliever used for relief from severe pains like post-operative pain or pain due to terminal cancer. 24. (i) Give chemical tests to distinguish between the following compounds (one test in each case). (a) Aniline and ethylamine (b) Methylamine and dimethylamine (ii) How will you convert aniline to sulphanilic acid ? SIR.S.M.TAHIR Mob: 9557076999 (8) SAMPLE QUESTION PAPER VMCC CHEMISTRY Or An aromatic compound (A) on treatment with ammonia followed by heating forms compound (B), which on heating with Br2 and KOH forms a compound (C) having molecular formula C6H7N. Give the structures of A, B and C and write the reactions involved. 25. Ethanol is used for drinking purpose. But to refrain people from drinking industrial alcohol it is denatured. Now-a-days, some countries now use ethanol as an additive in gasoline since it is cleaner fuel. 26. 27. (i) What is denatured alcohol ? Why it is denatured ? (ii) Would you support the use of ethanol as an additive in gasoline for India ? (iii) What are the values associated with you decision ? Give reasons (i) Interhalogen compounds are more reactive than halogens. (ii) PCl5 is known but NCl5 is not known. (iii) Amongst all noble gases only xenon is known to form compounds with oxygen and fluorine. (i) Give one main difference between lyophilic and lyophobic colloids. (ii) Explain shape selective catalysis with a suitable example. Section – D 28. (i) Two electrolytic cells containing silver nitrate solution and dilute sulphuric acid solution were connected in series. A steady current of 2.5 A was passed through them till 1.078 g of silver was depsited. [Ag = 107.8 g mol-3, IF = 96500 C] (a) How much electricity was consumed ? (b) What was the weight of oxygen gas liberated ? (ii) Give reason. (a) The equilibrium constant K is related to and not Ecell. (b) Conductivity of an electrolytic solution decreases with the decrease in concentration. Or (i) What is a fuel cell ? What is its main advantage ? (ii) What are the reactions occurring at the cathode and anode of a Leclanche cell ? (iii) In the button cell widely used for watches and other devices, the following reaction take place Zn(s) + Ag2O(s) + H2O(l) Zn2+ (aq) + 2Ag(s) + 2H- (aq) Give the cell representation and determine the value of K c for the above reaction using the following data Ag2O + H2O(l) + 2e- 2Ag(s) + 2OH- (aq) Eo = 0.344 V Zn2+ (aq) + 2e- Zn(s) (E0 = - 0.76 V) [Ans. (i) = Q = 965 C, (ii) Weight of oxygen gas liberated = 0.08 g (iii) K = 2.20 10 ] Or 37 SIR.S.M.TAHIR Mob: 9557076999 29. (8) SAMPLE QUESTION PAPER VMCC CHEMISTRY Explain the following. (i) MnO is less covalent than Mn2O7. (ii) Copper forms complex compounds. (iii) Chromium is a typical hard metal while mercury is a liquid. (iv) MnO is basic white Mn2O7 is acidic in nature. (v) Silver is a transition metal but zinc is not. (ii) Complete the following reactions. (a) Mn + S2 + Sn + H+ (b) Cr2 (iii) + H2O 2+ Which of the following has maximum number of unpaired electrons ? Ti2+ , V3+, Fe2+, Mg2+ (iv) Based on the data, arrange Fe2+, Mn2+ and Cr2+ in the increasing order of stability of +2 oxidation state. Eo (Cr3+ / Cr2+) = - 0.4 V E0 (Mn3+ / Mn2+) = 1.5 V E0 (Fe3+ / Fe2+) = 0.8 V 30. (i) Identify A, B and C in the following reaction. CH CH (ii) A Dil. NaOH B Heat C Give reasons (a) p-nitro benzoic acid has higher Ka value than benzoic acid. (b) Acetone is highly soluble in water but benzophenone is not. Or (i) An organic (A) has molecular formula (C5H10O). It does not reduce Tollen’s reagent but forms an orange precipitate with 2,4-DNP reagent. It forms a carboxylic acid (B) with molecular formula (C3H6O2) when treated with alkaline KMnO4, and a yellow precipitate on treatment with NaOH and I2. On oxidation under vigorous conditions gives ethanoic acid and propanoic acid. Sodium salt of (B) gave a hydrocarbon (C) in Kolbe’s electrolytic reduction. Identify (A), (B) and (C) and write the reactions involved. (ii) Predict the products formed in the following cases. (a) (A) reacts with PhMgBr and is then hydrolysed. (b) (A) reacts with hydrazine and is then heated with KOH ethylene glycol. SIR.S.M.TAHIR Mob: 9557076999 (9) SAMPLE QUESTION PAPER VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are compulsory 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. Why does the electrical conductivity of semiconductors increase with rise in temperature ? 2. Name the two ores which can be concentrated by magnetic separation method ? 3. Why does PCl3 fume in moisture ? 4. Write the IUPAC name of Cl 5. Arrange the following compounds in order of reactivity towards S N1 displacement. 1.bromobutane, 1-bromo-2-,2-dimethyl propane, 1-bromo-2-methyl butane, 1-bromo-3-methyl butane. 6. Write the structure of 4-methylhex-3-ene-2-one. 7. Why are amines less acidic than alcohols of comparable molecular masses ? 8. How are oligopeptides different from polypeptides ? Section – B 9. Calculate normal boiling point of a sample of sea water containing 3.5 % of NaCl and 0.13% of MgCl2 by mass. (Given kb (water = 0.52 kgmol-1, mol. Wt. of NaCl = 58.5 g mol-1, MgCl2 = 95 g ml-1) (Ans. 373.65 K) 10. Calculate the minimum potential difference required Al2O3 at 500 C. The free energy change G for the 0 decomposition reaction. Al2O3 Al + O2 is 960 kJ (1 F = 96500 C mol-1) [Ans. = -2.48 V] 11. Explain the following terms (i) Electro kinetic potential (ii) Phase of a colloidal solution Or Draw a plot of variation in quantity of gas adsorbed between log with the pressure of the gas. Also plot graph vs log p at constant temperature. What is the slope of this line ? 12. Differentiate between homogeneous and heterogeneous catalysis with one example of each. 13. Wrought iron is the purest form of iron. Write reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron ? 14. What happens when (i) Cl2 reacts with hot conc. NaOH ? SIR.S.M.TAHIR Mob: 9557076999 (ii) SAMPLE QUESTION PAPER (9) VMCC CHEMISTRY NaCl is heatd with sulphuric acid in the presence of MnO2 Write the reactions involved. 15. (i) In the first transition series (3d series), the enthalpy of atomization of Zn is lowest , i.e., 126 kJ mol-1. Why ? (ii) 16. Mention any two processes where transition metals act as catalysts. Why are haloarenes more stables than haloalkanes and undergo electrophilic substitution reaction at ortho and para position ? 17. Which of the following a appropriate set reactants for the preparation of 1-methoxy-4-nitrobenzene and why ? Br ONa (i) + CH3ONa (ii) + CH3Br Br 18. NO2 How will you convert ? (i) Methyl magnesium bromide to 2-methyl propan-2-ol (ii) Benzyl chloride to benzyl alcohol Section – C 19. 20. Explain the following terms (i) Schottky defect (ii) Interstitial defect (iii) F-centres (i) A 4% solution of sucrose is isotonic with 3% solution of an unknown organic substance. (ii) 21. Calculate the molecular mass of unknown substance. [Ans. 256.5 g mol-1] What is the mole fraction of solute in 2.5 M aqueous solution ? [Ans. 0.043] Explain the term electrolysis. Write the reactions at cathode and anode when following substances are electrolysed 22. (i) A dilute solution of H2SO4 with platinum electrodes. (ii) An aqueous solution of CuCl2 with platinum electrodes. (i) The electronic configuration of an element is 3d5, 4s2. Write its (a) most stable oxidation state and (b) most oxidizing state. (ii) Why is HCl not used to acidify a permanganate solutions in volumetric estimations of Fe2+ or C2 (iii) ? The size of the trivalent cations in the lanthanide series decreases steadily as the atomic number increases. What is the name of this process ? Or Complete the following equations, (i) Cr2 + 3H2S + 14H+ (ii) C SIR.S.M.TAHIR Mob: 9557076999 23. SAMPLE QUESTION PAPER (9) (iii) n (i) Write the chemical formulae of the following complexes VMCC CHEMISTRY + H2O- + 3S2 (a) Hexaamine platinum (IV) chloride (b) Tetraamine dichloro cobalt (III) iron (ii) Using valence bond theory of bonding in the complexes, explain the geometry and magnetic nature of [Co(NH3)6]3+ . (Atomic number of Co = 27) 24. 25. 26. How will you convert ? (i) Hexanenitrile into 1-aminopentane (ii) Nitromethane into dimethyl amine (iii) 3-methyl aniline into 3-nitrotoluene Explain the following processes with a suitable example in each case. (i) Chain growth polymeristion (ii) Step growth polymerisation During her teaching Prof. Amita Sharma noticed that some girls are weak in their studies. She discussed about this matter with those girls. During the discussion girls told her after reaching home from the college, they could not study for 3 to 4 hours. She also came to know that they were conscious to maintain their figure and for this reason they eat less food. Prof. Amita Sharma told them about the importance of balanced diet. 27. (i) What values are expressed by prof. Amita Sharma ? (ii) The Deficiency of which vitamin causes the disease pernicious anaemia . (iii) State the activity of oxidoreductase enzymes. (i) Why ae cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide ? (ii) How do antiseptics differ from disinfectants ? Give one example of each. (iv) What do you understand by broad spectrum antibiotics ? Is penicillin a broad spectrum antibiotic ? Section – D 28. (i) (a) Writ the rate law for a first order reaction. (b) Justify the statement that half-life of a first order reaction is independent of the initial concentration of the reactant. (ii) The rate constant of a reaction is 0.01439 min-1 at 250C and its activation energy is 70,000 J mol -1. What is the value of rate constant at 400C ? (R = 8.314 J K-1 mol-1) (Ans. 0.056 min-1) Or (i) What are pseudo unimolecular reactions ? Give two examples (ii) Consider the following data for the reaction, A + B products. Exp. Initial conc. [A] Initial conc. [B] Initial rate [Mole L-1 s-1] 1. 0.10 M 1.00 M 2.1 10-3 2. 0.20 M 1.00 M 8.4 10-3 3. 0.20 M 2.00 M 8.4 10-3 Determine the order of reaction with respect to ‘A’ and with respect to ‘B’ and the overall order of reaction. SIR.S.M.TAHIR Mob: 9557076999 29. (i) SAMPLE QUESTION PAPER (9) VMCC CHEMISTRY Give reasons for the following (a) Bleaching of flowers by Cl2 is permanent, while that by SO2 is temporary. (b) H2S is less acidic than H2Te (c) H3PO3 is diprotic. (ii) Complete the following chemical reaction equations, (a) CaF2 + H2SO4 (b) 2F2 + 2H2O Or (i) (a) Although electron gain enthalpy of fluorine is less negative as compared to chlorine, fluorine is a stronger oxidizing agent than chlorine. Why ? (ii) 30. (i) (b) Perchloric acid is a stronger acid than sulphuric acid. Why ? (c) Nitric oxide becomes brown when released in air. Explain. Arrange the following in decreasing order of property indicated. (a) NH3, PH3, AsH3, SbH3 (base strength) (b) F2, Cl2, Br2, I2 (bond energy) (c) HF, HCl, HBr, HI (boiling point) (d) H2O, H2S, H2Se, H2Te (HEH angle) Write reactions for obtaining (a) Phenyl acetic acid from benzene (b) But-2-enoicacid from ethanal (c) 3-nitro benzoic acid from 3-nitro bromo benzene (ii) Write one chemical equation for each to illustrate the following reactions (a) Rosenmund reduction (b) Clemmensen reduction Or (i) Write chemical tests to distinguish between (a) Phenol and propanoic acid (b) Acetic acid and acetaldehyde (c) Benzaldehyde and acetophenone (ii) What is meant by the following terms ? Give an example in each case (a) Semicarbazone (b) 2, 4,-DNP derivative SIR.S.M.TAHIR Mob: 9557076999 SAMPLE QUESTION PAPER (10) VMCC Time : 3 Hrs CHEMISTRY Max. Marks : 70 GENERAL INSTRUCTIONS 1. All questions are 2. Questions numbers 1 to 8 are very short answer questions and carry 1 mark each. 3. Questions numbers 9 to 18 are short answer questions and carry 2 marks each. 4. Questions numbers 19 to 27 are also short answer questions and carry 3 marks each. 5. Question numbers 28 to 30 are long answer questions and carry 5 marks each. 6. Use log tables if necessary, use of calculator is not allowed. Section – A 1. What is the number of octahedral voids in a unit cell of a cubic close packed structure ? 2. What is the rote of flux in metallurgical processes ? 3. Write the IUPAC name of m-ClCH2C6H4CH2C(CH3)3. 4. What happens when but-1-ene is treated with HBr in presence of peroxide ? 5. Write the structure of H2SO5 6. What are acetals ? Write general structure of an acetal. 7. Give one chemical test to distinguish between ethylamine and aniline. 8. Name the location where protein synthesis occurs in our body. Section – B 9. A sugar syrup of weight 214.2 g contains 34.2 g of sugar (C12H11). Calculate (i) mole fraction of sugar (ii) molality of sugar syrup. (Ans. (i) 0.00099 10. (ii) 0.55 m) Give an example where physisorption changes to chemisorptions with rise in temperature. Explain the reason for change. 11. Calculate Ecell for the cell Al(1) Al3+(0.01) M || Fe2+ (0.02 M) | Fe Given that = - 1.66 V and = - 0.44 V [Ans.1.19 V] 12. How are the following sols produced ? (i) Sulphur solution (ii) Collodion Or What are micelles ? How do they differ from ordinary colloidal particles ? Give two examples of micelle forming substances. 13. Describe the role of (i) Co in the Mond process for refining nickel (ii) NaCN in concentration of ore containing ZnS and PbS. 14. Explain why cleavage of phenyl alkyl ether with HBr always gives phenol and alkyl bromide. 15. What happens when ? (i) SO2 is passed through an aqueous solution of Fe (III) salt (ii) PCl5 is hydrolysed Write the reaction involved. SIR.S.M.TAHIR Mob: 9557076999 16. (i) SAMPLE QUESTION PAPER (10) VMCC CHEMISTRY Why is the +2 xidation state of manganese quite stable while the same is not true fro (Fe) iron (Mn = 25, Fe = 26) ? (ii) What are paramagnetic substances ? How does the paramagnetic character of the bivalent ions of first transition metal series vary from Ti (Z = 22) to copper (Z = 29) ? (CH3)3COH + Br- 17. Explain the mechanism of the following reaction, (CH3)3CBr + 18. Name the starting material used in the industrial preparation of phenol. Write complete reaction for the bromination of phenol in aqueous and non-aqueous medium. Section – C 19. (i) What type of defect can arise when a solid is heated ? Which physical property is affected by it ? (ii) What type of substances would make better permanent magnets, ferromagnetic or ferromagnetic ? Justify your answer. (iii) 20. Under which situations can an amorphous substance change to crystalline form ? 2 g of benzoic acid (C6H5COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.69 K. Molal depression constant of benzene is 4.9 K kg mol -1. What is the percentage association of acid if it forms dimer in solution ? 21. [Ans. 99.5%] For the electrode Pt, H2(1atm / H+ (aq) (XM), the reduction potential at 250C is -0.34 V. Write the electrode reaction equation and calculate the value of ‘X’. How will you deduce pH of the solution from the result ? [Ans. 1.778 10-6 mol L-1, pH = 575] 22. (i) Write the steps in the preparation of (a) KMnO4 from pyrolusite ore (b) K2Cr2O7 from chromite ore (ii) Give balanced chemical equations of two reactions in which KMnO4 acts as an oxidizing agent in the acidic medium. Or (i) Which trivalent cation is largest in the lanthanide series ? (ii) The electronic configuration of Co2+ and Cu2+ is d7 and d9 respectively. Which of these ions is expected to be more paramagnetic ? (iii) 23. Out of Cu2+ and Cr3+, which one is stable in aqueous solution ? Give reason. The hexaaqua manganese (II) ion contains five unpaired electrons while the hexacyano ion contains only one unpaired. Explain using crystal field theory. 24. 25. Account for the following (i) Aniline is acetylated to prepare monobromo derivative (ii) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (iii) C6H5N+(CH3)3 OH- is stronger base than NH4OH. Write the information asked for in the following polymers. (i) PVC-monomer unit (ii) Bakelite-materials used for preparation. (iii) Rubber-main purpose of vulcanization of rubber. (iv) Glyptal-monomer units (v) Low density polythene-conditions of temperature, pressure and name of catalyst SIR.S.M.TAHIR Mob: 9557076999 HN N (vi) N SAMPLE QUESTION PAPER (10) VMCC CHEMISTRY NH-CH2 N NH | N Monomer of this polymeric structure. 26. (i) Write down the structures and names of product formed when D-glucose is treated with (a) bromine water (b) HI (c) nitric acid (ii) 27. State difference between globular and fibrous proteins. Give one example of each. One day Prof. Amita’s maid Reena came to her and told that she is having high fever and body pain. Amita consoled her and suggest to take a glass of milk and some biscuits and then take the medicine after 15 minutes and told her that after half an hour she would feel better. (i) What values are expressed by Prof. Amita ? (ii) Which medicine Prof. Amita gave to her maid ? (iii) Why Prof. Amita suggest her to take some food before taking medicine ? Section – D 28. (i) The half-life for the decomposition of nitramide is 2.1 hour at 150C . NH4NO2(aq) N2O(g) + H2O (l) If 6.2 g of NH4NO2 is allowed to decompose, calculate (a) Time taken for NH4NO2 to decompose 99 %. (b) Volume of N2O(dry) produced at STP. [Ans. 13.96 h, 2.217 L] (ii) The first order rate constant for the decomposition of ethyl iodide by the reaction, C2H5I(g) C2H4(g) + HI (g) at 600 K is 1.60 10 s . Its energy of activation is 209 kJ mol-1. Calculate the rate constant of -5 -1 the reaction at 700 K [Ans. 6.36 10-3 s-1] Or (i) Sucrose decomposes in acid solution in to glucose and fructose according to the first order rate law, with t1/2 = 3.00 hours. What fraction of sample of sucrose remains after 8 hours ? (ii) The activation energy of first order reaction at 300 K is 60 kJ mol -1 . In presence of a catalyst, the activation energy gets lowered to 50 kJ mol -1 at 300 K. How many times the reaction rate change in the presence of a catalyst at same temperature ? 29. (i) Account for the following . (a) NH3 is stronger base than PH3. (b) Bismuth is a strong oxidizing agent in pentavalent state. (c) Of all the noble gases only xenon is known to form established chemical compounds. (ii) Apply VSEPR theory to deduce the structures of ClF3 and XeOF4. Or (i) (a) Name two poisonous gases which can be preapared from chlorine gas and also write their structural formulae. (b) SCl6 is not known but SF6 is known. Explain. SIR.S.M.TAHIR Mob: 9557076999 (c) (ii) SAMPLE QUESTION PAPER (10) VMCC CHEMISTRY NO2 is coloured but its dimer N2O4 is colourless. Explain Draw the structural formulae of the following (a) IF5 (b) HOClO2 30. (i) Write chemical reactions to affect the following transformations. (a) Butanal to butanoic acid (b) Acetyl chloride to acetone (c) 4-methyl acetophenone of benzene 1,4-dicarboxylic acid (ii) Give an example of each with necessary reaction conditions. (a) Fehling’s test (b) Aldol condensation Or (i) An organic compound ‘A’ has the molecular formula C5H10O. It does not reduce Fehling’s solution but forms a bisulphate compound. It also gives positive iodoform test. What are possible structures of ‘A’ ? Explain your reasoning which helped to arrive to the structures. (ii) Account for the following (a) Formaldehyde gives cannizzaro’s reaction where acetaldehyde does not. (b) Carboxylic acid do not give characteristic reactions of carbonyl group.
© Copyright 2020