Aniline is insoluble in water but soluble in dilute HCl.
Soluble anilinium ion is not a nucleophile so sodium acetate is necessary to deprotonate it. Sodium acetate must be added immediately after the acetic anhydride because the acetic anhydride starts hydrolyzing right away. If the CH 3 of the acetyl protecting group were labelled with 14C you would be able to detect 14C in the final sulfanilamide product. Complete the equation that depicts the equilibrium reaction between the anilinium ion and acetate ion. Show a reasonable mechanism for the formation of acetanilide from aniline and acetic anhydride.