Predict the products of the following reactions:
(i) CH₃-C(=O)H + H₂N-NH₂ →
(ii) C₆H₅-CH₃ (a) KMnO₄/KOH → (b) H⁺
(iii) Ph-COOH + Br₂/FeBr₃ →

(i) The reaction of acetaldehyde (CH₃CHO) with hydrazine (H₂N-NH₂) is a hydrazone formation reaction. The carbonyl group (C=O) reacts with hydrazine to form a hydrazone (CH₃-CH=N-NH₂).

CH₃-C(=O)H + H₂N-NH₂ → CH₃-CH=N-NH₂ + H₂O

(ii) This is a two-step reaction involving the oxidation of toluene (C₆H₅-CH₃) followed by acidification.

(a) Oxidation with KMnO₄/KOH oxidizes the methyl group (-CH₃) to a carboxyl group (-COOH), forming benzoic acid (C₆H₅-COOH).

C₆H₅-CH₃ + KMnO₄/KOH → C₆H₅-COOK → C₆H₅-COOH

(b) Acidification (with H⁺) converts the potassium benzoate (C₆H₅-COOK) to benzoic acid (C₆H₅-COOH).

(iii) This reaction involves electrophilic aromatic substitution. Bromine (Br₂) in the presence of a Lewis acid catalyst, iron(III) bromide (FeBr₃), adds to the benzene ring of benzoic acid. The -COOH group is a meta-directing group. Therefore, bromination occurs predominantly at the meta position.

Ph-COOH + Br₂/FeBr₃ → m-Br-C₆H₄-COOH + HBr