In the following sequence of reactions, the maximum number of atoms present in molecule ‘C’ in one p — Hydrocarbons Chemistry Question

💡 Solution & Explanation

**Step 1: Identify compound A** The lowest molecular weight alkyne is ethyne (acetetylene): HC≡CH **Step 2: Determine compound B** Ethyne undergoes hydration to form acetaldehyde: HC≡CH + H₂O → CH₃CHO (compound B) **Step 3: Determine compound C** Acetaldehyde undergoes aldol condensation (self-condensation under basic conditions): 2 CH₃CHO → CH₃CH(OH)CH₂CHO (aldol product, compound C) **Step 4: Analyze the structure of C** Compound C is 3-hydroxybutanal with structure: CH₃-CH(OH)-CH₂-CHO **Step 5: Identify coplanar atoms** To find maximum atoms in one plane, we analyze the structure: - The C₁-C₂-C₃-C₄ carbon backbone can lie in one plane - The OH group on C₂ can be in-plane - The H atoms on the carbons can be positioned in-plane - The O atom of the aldehyde group can be in-plane Counting atoms in one plane: - 4 carbon atoms - 1 oxygen (from OH) - 1 oxygen (from CHO) - 7 hydrogen atoms (from CH₃, CH, CH₂, and CHO groups) Total: 4 + 1 + 1 + 7 = **13 atoms** Therefore, the answer is 13.00.