(a)[1]
Name the group that is present in tartaric acid but absent in succinic acid.
(b)[2]
When tartaric acid is reduced to succinic acid by acidified aqueous potassium iodide, what colour change would you observe in the reaction mixture?
(c)[1]
Succinic acid is a weak acid. What does the term weak acid mean?
(d)[3]
Aqueous sodium hydroxide neutralises succinic acid. $\text{C}_2\text{H}_4(\text{COOH})_2+2\text{NaOH}\rightarrow \text{C}_2\text{H}_4(\text{COONa})_2+2\text{H}_2\text{O}$. Calculate the least volume of $0.0200\,\text{mol dm}^{-3}$ sodium hydroxide needed to neutralise $25.0\,\text{cm}^3$ of $0.0500\,\text{mol dm}^{-3}$ succinic acid. Give your answer to three significant figures.