GSEB Std 12 Science Question Paper 2020 Chemistry (English Medium)

UNIT TEST STANDARD- 12 Total Marks:25 SUBJEST-CHEMISTRY Time: 1-Hour CODE-052 Medium: English PART-A  Select the proper choice and answer the following multiple choice questions. (Each question is of 1 mark) [09] 1. Maximum covalency of nitrogen is ______________. (A) 3 (B) 5 (C) 4 (D) 6 2. Which of the following are peroxoacids of sulphur? (A) H2SO5 and H2S2O8 (B) H2SO5 and H2S2O7 (C) H2S2O7 and H2S2O8 (D)H2S2O6and H2S2O7 3. Which of the following alcohols will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature? (A) CH3CH2—CH2—OH (B) CH3-CH2-CH(CH3)-OH (C) CH3-CH2-CH(CH3)-CH2OH (D) CH3-CH2-C(CH3)2-OH 4. Which of the following alkyl halides will undergo SN1 reaction most readily? (A) (CH3)3C—F (B) (CH3)3C—Cl (C) (CH3)3C—Br (D) (CH3)3C—I 5. Which of the following compounds will react with sodium hydroxide solution in water? (A) C6H5OH (B) C6H5CH2OH (C) (CH3)3 COH (D) C2H5OH 6. Which of the following is benzylic alcohol? (A) C6H5CH2CH2OH (B) C6H11CH2OH (C) C6H5CH(OH)CH3 (D) C6H5CH2CH(OH)CH3 7. Cannizaro’s reaction is not given by _____________. (A) 1-Methylcyclohexane carbaldehyde (B) Benzene carbaldehyde (C) Methanal (D) Ethanal 8. In Clemmensen Reduction carbonyl compound is treated with _____________. (A) Zinc amalgam + HCl (B) Sodium amalgam + HCl (C) Zinc amalgam + HNO3 (D) Sodium amalgam + HNO3 9. The correct order of increasing acidic strength is _____________. (A) Phenol < Ethanol < Chloroacetic acid < Acetic acid (B) Ethanol < Phenol < Chloroacetic acid < Acetic acid (C) Ethanol < Phenol < Acetic acid < Chloroacetic acid (D) Chloroacetic acid < Acetic acid < Phenol < Ethanol 1

PART-B SECTION A  Answer any three of the following questions. (Each question is of 2 marks) [06] 1. How the following conversion can be carried out? tert-Butyl bromide to isobutyl bromide 2. Explain Wurtz Fittig reaction giving suitable example. 3. Give bromination reactions of phenol under different conditions. 4. Write structures of the products of the following reactions: 5. Write the structures of the following compounds. (i) -Methoxypropionaldehyde (ii) 2-Hydroxycyclopentane carbaldehyde SECTION B  Answer any two of the following questions. (Each question is of 3 marks) [06] 6. Complete and balance the following reactions: (i). Cu + HNO3(dilute)  (ii). Zn + NHO3 (conc)  (iii). P4 + HNO3 (conc)  7. What are ambident nucleophiles? Explain with an example. 8. Give the major products that are formed by heating each of the following ethers with HI. SECTION C  Answer any one of the following questions. (Each question carries 4 marks) [4] 9. Explain cross aldol condensation reaction. 10. Answer the following questions as asked: (i). Give two examples to show the anomalous behaviour of fluorine. (2 marks) (ii). How are XeO3 and XeOF4 prepared? (2 marks) --------x----------x--------- 2