Chemistry sample paper, Exams of Chemistry

Download Chemistry sample paper and more Exams Chemistry in PDF only on Docsity! 1 SAMPLE PAPER (2022-23) CHEMISTRY THEORY (043) MM:70 Time: 3 hours General Instructions: Read the following instructions carefully. a) There are 35 questions in this question paper with internal choice. b) SECTION A consists of 18 multiple-choice questions carrying 1 mark each. c) SECTION B consists of 7 very short answer questions carrying 2 marks each. d) SECTION C consists of 5 short answer questions carrying 3 marks each. e) SECTION D consists of 2 case- based questions carrying 4 marks each. f) SECTION E consists of 3 long answer questions carrying 5 marks each. g) All questions are compulsory. h) Use of log tables and calculators is not allowed SECTION A The following questions are multiple-choice questions with one correct answer. Each question carries 1 mark. There is no internal choice in this section. 1. The major product of acid catalysed dehydration of 1-methylcyclohexanol is: a. 1-methylcyclohexane b. 1-methylcyclohexene c. 1-cyclohexylmethanol d. 1-methylenecyclohexane 2. Which one of the following compounds is more reactive towards SN1 reaction? a. CH2=CHCH2Br b. C6H5CH2Br c. C6H5CH (C6H5)Br d. C6H5CH(CH3) Br 3. KMnO4 is coloured due to: a. d-d transitions b. charge transfer from ligand to metal c. unpaired electrons in d orbital of Mn d. charge transfer from metal to ligand 2 4. Which radioactive isotope would have the longer half- life 15O or 19O? (Given rate constants for 15O and 19O are 5.63x 10-3 s-1 and k = 2.38 x 10-2s-1 respectively.) a. 15O b. 19O c. Both will have the same half-life d. None of the above, information given is insufficient 5. The molar conductivity of CH3COOH at infinite dilution is 390 Scm2/mol. Using the graph and given information, the molar conductivity of CH3COOK will be: a. 100 Scm2/mol b. 115 Scm2/mol c. 150 Scm2/mol d. 125 Scm2/mol *FOR VISUALLY CHALLENGED LEARNERS *5. What is the molar conductance at infinite dilution for sodium chloride if the molar conductance at infinite dilution of Na+ and Cl- ions are 51.12 × 10-4 Scm2/mol and 73.54× 10-4 Scm2/mol respectively? a. 124.66 Scm2/mol b. 22.42 Scm2/mol c. 198.20Scm2/mol d. 175.78 Scm2/mol 5 Assertion (A): An ether is more volatile than an alcohol of comparable molecular mass. Reason (R): Ethers are polar in nature. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true. 16. Given below are two statements labelled as Assertion (A) and Reason (R) Assertion (A): Proteins are found to have two different types of secondary structures viz alpha-helix and beta-pleated sheet structure. Reason (R): The secondary structure of proteins is stabilized by hydrogen bonding. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true. 17. Given below are two statements labelled as Assertion (A) and Reason (R) Assertion : Magnetic moment values of actinides are lesser than the theoretically predicted values. Reason : Actinide elements are strongly paramagnetic. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true. 18. Given below are two statements labelled as Assertion (A) and Reason (R) Assertion (A): Tertiary amines are more basic than corresponding secondary and primary amines in gaseous state. Reason (R): Tertiary amines have three alkyl groups which cause +I effect. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true. SECTION B 6 This section contains 7 questions with internal choice in two questions. The following questions are very short answer type and carry 2 marks each. 19. A first-order reaction takes 69.3 min for 50% completion. What is the time needed for 80% of the reaction to get completed? (Given: log 5 =0.6990, log 8 = 0.9030, log 2 = 0.3010) 20. Account for the following: a. There are 5 OH groups in glucose b. Glucose is a reducing sugar OR What happens when D – glucose is treated with the following reagents a. Bromine water b. HNO3 21. Give reason for the following: a. During the electrophilic substitution reaction of haloarenes, para substituted derivative is the major product. b. The product formed during SN 1 reaction is a racemic mixture. OR a. Name the suitable alcohol and reagent, from which 2-Chloro-2-methyl propane can be prepared. b. Out of the Chloromethane and Fluoromethane , which one is has higher dipole moment and why? 22. The formula Co(NH3)5CO3Cl could represent a carbonate or a chloride. Write the structures and names of possible isomers. 23. Corrosion is an electrochemical phenomenon. The oxygen in moist air reacts as follows: O2(g) + 2H2O(l) + 4e– → 4OH– (aq). Write down the possible reactions for corrosion of zinc occurring at anode, cathode, and overall reaction to form a white layer of zinc hydroxide. 24. Explain how and why will the rate of reaction for a given reaction be affected when a. a catalyst is added b. the temperature at which the reaction was taking place is decreased 25. Write the reaction and IUPAC name of the product formed when 2-Methylpropanal (isobutyraldehyde) is treated with ethyl magnesium bromide followed by hydrolysis. 7 SECTION C This section contains 5 questions with internal choice in two questions. The following questions are short answer type and carry 3 marks each. 26. Write the equations for the following reaction: a. Salicylic acid is treated with acetic anhydride in the presence of conc. H2SO4 b. Tert butyl chloride is treated with sodium ethoxide. c. Phenol is treated with chloroform in the presence of NaOH 27. Using Valence bond theory, explain the following in relation to the paramagnetic complex [Mn(CN)6]3- a. type of hybridization b. magnetic moment value c. type of complex – inner, outer orbital complex 28. Answer the following questions: a. State Henry’s law and explain why are the tanks used by scuba divers filled with air diluted with helium (11.7% helium, 56.2% nitrogen and 32.1% oxygen)? b. Assume that argon exerts a partial pressure of 6 bar. Calculate the solubility of argon gas in water. (Given Henry’s law constant for argon dissolved in water, KH = 40kbar) 29. Give reasons for any 3 of the following observations: a. Aniline is acetylated before nitration reaction. b. pKb of aniline is lower than the m-nitroaniline. c. Primary amine on treatment with benzenesulphonyl chloride forms a product which is soluble in NaOH however secondary amine gives product which is insoluble in NaOH. d. Aniline does not react with methyl chloride in the presence of anhydrous AlCl3 catalyst. 30. a. Identify the major product formed when 2-cyclohexylchloroethane undergoes a dehydrohalogenation reaction. Name the reagent which is used to carry out the reaction. b. Why are haloalkanes more reactive towards nucleophilic substitution reactions than haloarenes and vinylic halides? OR a. Name the possible alkenes which will yield 1-chloro-1-methylcyclohexane on their reaction with HCl. Write the reactions involved. b. Allyl chloride is hydrolysed more readily than n-propyl chloride. Why? 10 lifetime? b. Write the reaction occurring at anode and cathode and the products of electrolysis of aq KCl. c. What is the pH of HCl solution when the hydrogen gas electrode shows a potential of -0.59 V at standard temperature and pressure? OR a. Molar conductivity of substance “A” is 5.9×103 S/m and “B” is 1 x 10-16 S/m. Which of the two is most likely to be copper metal and why? b. What is the quantity of electricity in Coulombs required to produce 4.8 g of Mg from molten MgCl2? How much Ca will be produced if the same amount of electricity was passed through molten CaCl2? (Atomic mass of Mg = 24 u, atomic mass of Ca = 40 u). c. What is the standard free energy change for the following reaction at room temperature? Is the reaction spontaneous? Sn(s) + 2Cu2+ (aq) à Sn2+ (aq) + 2Cu+ (s) 34. A hydrocarbon (A) with molecular formula C5H10 on ozonolysis gives two products (B) and ( C). Both (B) and (C) give a yellow precipitate when heated with iodine in presence of NaOH while only (B) give a silver mirror on reaction with Tollen’s reagent. a. Identify (A), (B) and (C). b. Write the reaction of B with Tollen’s reagent c. Write the equation for iodoform test for C d. Write down the equation for aldol condensation reaction of B and C. OR An organic compound (A) with molecular formula C2Cl3O2H is obtained when (B) reacts with Red P and Cl2. The organic compound (B) can be obtained on the reaction of methyl magnesium chloride with dry ice followed by acid hydrolysis. a. Identify A and B b. Write down the reaction for the formation of A from B. What is this reaction called? c. Give any one method by which organic compound B can be prepared from its corresponding acid chloride. d. Which will be the more acidic compound (A) or (B)? Why? e. Write down the reaction to prepare methane from the compound (B). 35. Answer the following: a. Why are all copper halides known except that copper iodide? b. Why is the Eo (V3+/V2+) value for vanadium comparatively low? c. Why HCl should not be used for potassium permanganate titrations? 11 d. Explain the observation, at the end of each period, there is a slight increase in the atomic radius of d block elements. e. What is the effect of pH on dichromate ion solution?