The following table gives the results of four electrophilic substitution reactions of chlorobenzene. (Sections 22.2-22.3)
\hline Reaction & $\%$ 2-substitution & \% 3-substitution & $\%$ 4-substitution \\
\hline Chlorination & 39 & 6 & 55 \\
Nitration & 30 & 0 & 70 \\
Bromination & 11 & 2 & 87 \\
Sulfonation & 1 & 0 & 99 \\
the electrophile could be
(a) Draw the structure of the major product of the sulfonation reaction.
(b) Draw the structure of the minor product of the nitration reaction.
(c) Explain, with reference to the stabilities of the reaction intermediates, why 2-substituted and 4 -substituted products are favoured in all four reactions.
(d) Suggest why the four reactions give different ratios of 2-substituted:4-substituted products.