In the first step, 4-sulfanilic acid reacts with sodium nitrate to form diazonium ion intermediate. Identify the Lewis acid and Lewis base in this reaction.

In the formation of diazonium ion intermediate, the 4-sulfanilic acid acts as the Lewis acid, while the sodium nitrite is the Lewis base.

Explanation:

A Lewis acid is by definition an electron pair acceptor (such as the H + ion, that can accept a pair of non-bonding electrons) and a Lewis base is an electron pair donor (such as the OH - ion, that can donate a pair of non-bonding electrons).

In the formation of diazonium ion intermediate, the 4-sulfanilic acid acts as the Lewis acid (by transference of a lone pair from its nitrogen atom), while the sodium nitrite is the Lewis base.

N. B its sodium nitrite, NaNO2 (which is slightly basic in solution) not nitrate NaNO3 (which is neutral in solution)