See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: When calcium hydroxide Ca(OH)2 reacts with a carboxylic acid, it first forms the calcium salt. When the calcium salt of a carboxylic acid is heated (dry distillation), it undergoes a ketonization reaction to produce a ketone. Step 1: Identify the starting material. The starting material is acetic acid (ethanoic acid), CH3COOH. Step 2: Reaction with Ca(OH)2. Two moles of acetic acid react with Ca(OH)2 to form calcium acetate: 2 CH3COOH + Ca(OH)2 → (CH3COO)2Ca + 2 H2O. Step 3: Dry distillation (pyrolysis) of calcium acetate. When calcium acetate is heated strongly, it undergoes dry distillation (ketonization): (CH3COO)2Ca --[Delta]--> CH3COCH3 + CaCO3. The two acetate groups combine, losing CaCO3, to give acetone (propan-2-one), CH3COCH3. Step 4: Identify the product. Acetone (CH3COCH3) corresponds to option (b), which shows a ketone with two methyl groups on either side of a carbonyl. Why other options fail: - (a) Propanal (CH3CH2CHO) is an aldehyde with 3 carbons; this would require a different carboxylic acid and a different reaction pathway. - (c) Isopropanol (CH3CH(OH)CH3) is an alcohol; Ca(OH)2 dry distillation does not produce alcohols. - (d) 1-Propanol (CH3CH2CH2OH) is also an alcohol; same reasoning as (c). Therefore, the correct answer is B.