Which of the following statements regarding the oxidation or...

Let us evaluate each statement.

Statement 1 is correct: Oxidation of $p$-nitrotoluene yields $p$-nitrobenzoic acid. The $-\text{NO}_2$ group is a strong electron-withdrawing group ($-I, -M$), making it a stronger acid than $p$-fluorobenzoic acid, where fluorine has a weaker net electron-withdrawing effect.

Statement 2 is correct: Reduction of $p$-nitroanisole yields $p$-anisidine. The $-\text{OCH}_3$ group is an electron-donating group ($+M > -I$), which increases electron density on the nitrogen, making it a stronger base than aniline.

Statement 3 is correct: Reduction of $m$-chloronitrobenzene yields $m$-chloroaniline. The chlorine atom exerts a $-I$ effect, withdrawing electron density and making it a weaker base than aniline.

Statement 4 is incorrect: Oxidation of $m$-methoxytoluene yields $m$-methoxybenzoic acid. At the meta position, the mesomeric ($+M$) effect of the $-\text{OCH}_3$ group does not operate. Only its inductive ($-I$) effect is felt at the carboxyl group. Because of this $-I$ effect, $m$-methoxybenzoic acid is actually a stronger acid than benzoic acid, not weaker.

Answer: Oxidation of $m$-methoxytoluene with acidic KMnO$_4$ gives an acid weaker than benzoic acid due to the $+M$ effect of the methoxy group.