IIT-JEE 2010 · Paper 1, Chemistry question 22

Soluble in aqueous NaOH means acidic enough to form a salt (carboxylic acids and phenols):

• cyclohexanecarboxylic acid: yes;
• phenol: yes;
• 4-(dimethylamino)phenol: yes (a phenol);
• 1-naphthoic acid: yes.

Not soluble: N,N-dimethylaniline (a base), 2-ethoxybenzyl alcohol (an alcohol, too weakly acidic), nitrobenzene and 1,2-diethylbenzene (neutral).

Answer: 4