The structures of three organic compounds are shown.
Which compounds produce ethanoic acid when heated with \(\mathrm{HCl(aq)}\)?
Correct Answer: \( \boxed{\mathrm{D}} \)
Compound 2 is a nitrile, which hydrolyses with aqueous acid to form ethanoic acid:
\(\mathrm{CH_3CN+2H_2O+H^+\rightarrow CH_3COOH+NH_4^+}\)
Compound 3 is an ester (methyl ethanoate), which hydrolyses with aqueous acid to produce ethanoic acid and methanol.
Compound 1 is ethanal, which is not converted to ethanoic acid simply by heating with aqueous hydrochloric acid.
Therefore, the correct answer is (D).
Which organic starting material could be used in a single reaction to produce propanoic acid?
Correct Answer: \( \boxed{\mathrm{C}} \)
Propanal is an aldehyde and can be oxidised directly to propanoic acid in a single reaction using an oxidising agent such as acidified potassium dichromate(VI) or potassium manganate(VII).
\(\mathrm{CH_3CH_2CHO+[O]\rightarrow CH_3CH_2COOH}\)
Ethanenitrile hydrolyses to ethanoic acid, propan-2-ol oxidises to propanone, and propyl ethanoate hydrolyses to propan-1-ol and ethanoic acid.
Therefore, the correct answer is (C).
In four separate reactions, W, X, Y and Z, \(1\,\mathrm{mol}\) of an organic compound reacts with an excess of a reagent.
| Organic compound | Reagent | |
|---|---|---|
| W | \(\mathrm{(CH_2COOH)_2}\) | Na |
| X | \(\mathrm{CH_3CH(OH)CH_2COOH}\) | \(\mathrm{Na_2CO_3}\) |
| Y | \(\mathrm{CH_3CH(OH)CH_2COOH}\) | NaOH |
| Z | \(\mathrm{CH(OH)(COOH)CH_2COOH}\) | Na |
The volume of any gas produced is collected and measured. All gas volumes are measured at the same temperature and pressure.
What is the order of the reactions from greatest total volume of gas collected to least total volume of gas collected?
Correct Answer: \( \boxed{\mathrm{C}} \)
Sodium reacts with both carboxylic acid and alcohol groups to produce hydrogen gas, whereas sodium carbonate reacts only with carboxylic acids to produce carbon dioxide, and sodium hydroxide produces no gas.
Therefore, the correct order is Z, W, X, Y, so the correct answer is (C).
