Question

Given below are two statements:
Statement I: On heating with KHSO₄, glycerol is dehydrated and acrolein is formed.
Statement II: Acrolein has fruity odour and can be used to test glycerol’s presence.
Choose the correct option

• A. Both Statement I and Statement II are correct.
• B. Both Statement I and Statement II are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Answer 1

The Correct Option is C

To solve this question, we need to examine both statements related to the chemistry of glycerol.

1. Statement I Explanation: This statement pertains to the chemical reaction involving glycerol. On heating glycerol with potassium hydrogen sulfate (KHSO₄), it undergoes dehydration. This results in the formation of acrolein, which is scientifically known as 2-propenal. The reaction can be represented as follows:

C_3H_8O_3 \ \xrightarrow{KHSO_4,\ heat} \ C_3H_4O + 2 \ H_2O

2. Statement II Explanation: This statement discusses the odor and test characteristics of acrolein. Acrolein does not have a fruity odor; instead, it is known to have a sharp, pungent smell. It is not used because of any fruity odor for testing glycerol; instead, the presence of acrolein due to its distinct smell is an indicator of glycerol undergoing dehydration.

In light of the above analysis, we conclude:

• Statement I is correct: The chemical reaction leading to the formation of acrolein from glycerol on heating with KHSO₄ is accurate.
• Statement II is incorrect: Acrolein does not possess a fruity odor; hence, this statement is false.

Therefore, the correct option is: Statement I is correct but Statement II is incorrect.