Give the IUPAC systematic name of M.
Name the functional group in M that is changed during this reaction.
State a suitable reagent for this reaction.
Separate samples of $1,3$-dichloropropan-$2$-ol and $3$-chloropropane-$1,2$-diol are each heated with excess acidified $\text{Cr}_2\text{O}_7^{2-}$ until the reaction is complete. In each case, a different organic product, $Q$ or $R$, is formed. $Q$ and $R$ are then tested separately with $2,4$-dinitrophenylhydrazine solution ($2,4$-DNPH) and sodium carbonate solution, $\text{Na}_2\text{CO}_3(aq)$. Fill in the table with any relevant observations. If there is no reaction, write ‘no visible change’.
Citric acid can be prepared from $M$ in a four-step reaction. Complete the table for each stage of the sequence by identifying: • the reagents and conditions needed • the reaction type.