Tiêu đề XII Chemistry 7 Years Slips (Pages 40 ).pdf ✅

268  Shivdas SENIOR SECONDARY SERIES (XII) Q.18. 18 g of a non–volatile solute is dissolved in 200 g of H2O freezes at 272.07 K. Calculate the molecular mass of solute (Kf for water = 1.86 K kg mol–1). 2 Q.19. (a) Which compound in the given pair would undergo SN2 reaction at a faster rate and why? CH3—CH2—I and CH3—CH2—Br (b) Arrange the following compounds in the increasing order of their boiling points: Butane, 1–Bromobutane, 1–Iodobutane, 1–Chlorobutane 1×2 Q.20. (a) Write the stepwise mechanism of nucleophilic addition reactions in the carbonyl compounds. 2 Or (b) How will you convert the following: 1×2 (i) Toluene to benzoic acid. (ii) Ethanol to 3–Hydroxybutanal. Q.21. (a) What happens when glucose reacts with bromine water? Write chemical equation. 1×2 (b) Two bases are mentioned below, identify which is present in DNA and which one is present in RNA: (i) Thymine (ii) Uracil. Section–C Q.22. (a) Draw the geometrical isomers of the given complex: 1×3 [Pt(en)2Cl2]2+ (b) Write the electronic configuration for d4 ion if ∆0 < P on the basis of crystal field theory. (c) What is meant by a unidentate ligand? Give an example. Q.23. Calculate emf of the following cell at 25 oC: 3 Sn | Sn2+ (0.001 M) || H+ (0.01 M) | H2(g) (1 bar) | Pt(s) Given: E°(Sn2+ | Sn) = –0.14 V, Eo H+ | H2 = 0.00 V, (log 10 = 1) Q.24. Write chemical equations for the following reactions: (Do any three) 1×3 (a) Hydroboration—oxidation reaction (b) Williamson Synthesis (c) Friedel–Crafts Alkylation of Anisole (d) Reimer–Tiemann Reaction Q.25. (a) Give chemical tests to distinguish between the following pairs of compounds: 2+1 (i) Phenol and Benzoic acid (ii) Propanal and Propanone (b) Which one of the given compounds is a stronger acid and why? CH2FCH2CH2COOH or CH3CHFCH2COOH Q.26. Explain the following terms: 1×3 (a) Essential amino acids (b) Peptide bond (c) Denaturation Q.27. (a) Write the IUPAC name of the given compound: 1×3 Cl Br