Q3. Give the products of hydrolysing (i) ethyl ethanoate with dilute acid, (ii) ethanoic anhydride with water, (iii) benzoyl chloride with aqueous NaOH followed by acid.
(i) CH3COOH and C2H5OH. (ii) Two molecules of CH3COOH. (iii) C6H5COO− first, then benzoic acid, C6H5COOH, on acidification (reasoned from NCERT page 247).
Q4. Which reagent turns hexan-1-ol into hexanoic acid, and which turns 4-methylbenzoic acid’s methyl group into a second –COOH?
Jones reagent (CrO3–H2SO4) or KMnO4 oxidises the primary alcohol; hot KMnO4 oxidises the methyl side chain, giving benzene-1,4-dicarboxylic acid (reasoned from NCERT pages 245–246).
Q5. Starting from 1-bromopropane, which acid do the cyanide and the Grignard routes give?
Butanoic acid, CH3CH2CH2COOH, one carbon more than the three-carbon halide (reasoned from NCERT pages 246–247).
Q6. What mass of benzoic acid can 9.2 g of toluene give at most on oxidation with KMnO4? (C = 12, H = 1, O = 16.)
9.2/92 = 0.10 mol of toluene gives 0.10 mol of C6H5COOH, M = 122 g mol−1: 0.10 × 122 = 12.2 g (reasoned from NCERT page 246).