Target Exam

CUET

Subject

Chemistry

Chapter

Organic: Biomolecules

Question:

Statement I: Cyclic acetal formation of glycols by glycose confirms the presence of a hydroxyl group

Statement II: Carbonyl compounds generally form acetals with alcohols

Options:

Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I

Both Statement I and Statement II are correct and Statement II is not the correct explanation of Statement I

Statement I is correct but Statement II is false

Statement I is false but Statement II is correct

Correct Answer:

Statement I is false but Statement II is correct

Explanation:

Statement I: Cyclic acetal formation of glycols by glycose confirms the presence of a hydroxyl group

Statement I is false. Cyclic acetal formation of glycols by glycose does not necessarily confirm the presence of a hydroxyl group. While glycols do have hydroxyl groups, the formation of cyclic acetals does not solely indicate the presence of a hydroxyl group. Cyclic acetals can be formed through the reaction of a carbonyl compound (aldehyde or ketone) with an alcohol, and the presence of a hydroxyl group is not a prerequisite for the formation of a cyclic acetal.

Statement II: Carbonyl compounds generally form acetals with alcohols

Statement II is correct.  Carbonyl compounds, which include aldehydes and ketones, can indeed form acetals with alcohols. Acetals are formed when a carbonyl group reacts with one or more alcohol groups in the presence of an acid catalyst. This reaction is a well-known method for the protection of carbonyl groups in organic synthesis.

Therefore, the correct answer is (4) Statement I is false, but Statement II is correct.