Question

Which of the following compounds is obtained by dry distillation of calcium propionate?

• A. Pentan-3-one
• B. Pentan-2-one
• C. Propanone
• D. Butan-2-one

Hint:

Dry distillation of calcium salts of carboxylic acids always gives symmetrical ketones.

Answer 1

The Correct Option is A

Step 1: Identify the reaction type.
Dry distillation of calcium salts of carboxylic acids results in the formation of symmetrical ketones. This reaction is also known as ketonic decarboxylation.

Step 2: Apply to calcium propionate.
Calcium propionate is the calcium salt of propanoic acid. On dry distillation, two propionyl groups combine to form a ketone.

Step 3: Write the reaction.
\[ \mathrm{(CH_3CH_2COO)_2Ca \xrightarrow{\Delta} CH_3CH_2COCH_2CH_3 + CaCO_3} \]

Step 4: Identify the product.
The ketone formed is \(\mathrm{CH_3CH_2COCH_2CH_3}\), which is pentan-3-one.

Step 5: Conclusion.
Thus, dry distillation of calcium propionate yields pentan-3-one.