Reductive ozonolysis of 2,3-dimethyl-1-butene followed by reduction with zinc and water gives.

Correct option: (b) Methanal and 3-methyl-2-butanone.

Step 1. Structure of 2,3-dimethyl-1-butene

• Base chain: but-1-ene (C=C at C1–C2).
• Substituents: C2 has a methyl group, C3 has a methyl group.
• Structure: CH₂=C(CH₃)–CH(CH₃)–CH₃.

Step 2. Ozonolysis rule

• Ozone cleaves the C=C double bond.
• Each carbon of the double bond becomes a carbonyl group.
• With reductive workup (Zn/H₂O), aldehydes/ketones form (not acids).

Step 3. Apply cleavage

• C1 = CH₂ of the double bond → gives methanal (HCHO).
• C2 = C attached to CH₃ and rest of chain → becomes a carbonyl with groups: methyl and isopropyl fragment → 3-methyl-2-butanone.

Step 4. Verify options

• (a) has methanoic acid — wrong (acid would come only in oxidative workup).
• (b) methanal + 3-methyl-2-butanone — correct.
• (c) methanoic acid again — wrong.
• (d) methanol + 2-methyl-2-butene — unrelated, wrong.

Final Answer

(b) Methanal and 3-methyl-2-butanone