Sunset Yellow is a colouring additive used in foods. The synthesis route for preparing Sunset Yellow is shown. Molecules E and G each have one $-\text{SO}_3^-$ group, and these groups remain unchanged during the formation of Sunset Yellow.
(a)[1]
State the molecular formula for the Sunset Yellow anion.
(b)[3]
Infer the structures of E, F and G and draw them in the boxes in Fig. 7.1.
(c)[3]
Suggest appropriate reagents and conditions for step 1 and step 2.
(d)[1]
Predict how many peaks appear in the carbon-13 NMR spectrum of the Sunset Yellow anion.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The molecular formula is $C_{16}H_{10}N_2O_7S_2^{2-}$” …