Benzophenone does not react with (a) \(\mathrm{NaHSO}_{3}\) (b) \(\mathrm{H}_{2} \mathrm{NOH}\) (c) \(\mathrm{HCN}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{MgBr}\)

Benzophenone is an organic compound with the molecular formula \(\mathrm{C}_{13} \mathrm{H}_{10} \mathrm{O}\). Its structure consists of two phenyl rings connected by a carbonyl group. The carbonyl group contains a carbon atom double-bonded to an oxygen atom, making it an electrophilic center. This electrophilic center can react with nucleophiles, converting Benzophenone into various other compounds.

(a) \(\mathrm{NaHSO}_{3}\): Sodium bisulfite is a mild reducing agent and reacts with aldehydes to form bisulfite adducts. However, Benzophenone is a ketone, not an aldehyde, and hence does not react with sodium bisulfite. (b) \(\mathrm{H}_{2} \mathrm{NOH}\): This reagent, hydroxylamine, reacts with both aldehydes and ketones to form oximes. Since Benzophenone is a ketone, it will react with hydroxylamine. (c) \(\mathrm{HCN}\): Hydrogen cyanide reacts with both aldehydes and ketones, by adding a nitrile group to the carbonyl group via nucleophilic addition to form cyanohydrins. So, Benzophenone will react with hydrogen cyanide. (d) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{MgBr}\): This reagent is phenylmagnesium bromide, a Grignard reagent. Grignard reagents are strong nucleophiles and react with carbonyl groups, which are present in Benzophenone. As a result, Benzophenone will react with phenylmagnesium bromide.

After analyzing all four reagents, we can conclude that Benzophenone does not react with Sodium bisulfite (\(\mathrm{NaHSO}_{3}\)). Therefore, the correct answer is (a) \(\mathrm{NaHSO}_{3}\).