Neco 2021 Chemistry Question 34

Practice objective / multiple choice question 34 from the 2021 Neco Chemistry examination.

Neco 2021 Chemistry Objective / Multiple Choice Medium Difficulty
Question 34 NECO • 2021 • CHEMISTRY • objective

A volatile organic compound has the molecular formula \(\mathrm{C_7H_8O_2}\) and its infrared spectrum shows a strong absorption at \(1715\ \text{cm}^{-1}\) characteristic of a carbonyl group. (a) Determine the degree of unsaturation of the compound. (b) Propose a plausible structural formula that is consistent with the molecular formula, the degree of unsaturation and the presence of a carbonyl group.

Answer Options

A. Degree of unsaturation = 3; a structure such as p‑hydroxybenzaldehyde (benzene ring with a formyl group) satisfies the formula and IR data
Correct Answer B. Degree of unsaturation = 4; a structure such as p‑hydroxyacetophenone (benzene ring with a carbonyl side‑chain) satisfies the formula and IR data
C. Degree of unsaturation = 4; a structure such as p‑hydroxyacetophenone (benzene ring with a carbonyl side‑chain) but with the carbonyl reduced to an alcohol (p‑hydroxyacetophenol) satisfies the formula and IR data
D. Degree of unsaturation = 5; a structure such as p‑hydroxyacetophenone with an additional double bond in the side chain (e.g., an α,β‑unsaturated ketone) satisfies the formula and IR data
Correct Answer
B
Correct Option:
Degree of unsaturation = 4; a structure such as p‑hydroxyacetophenone (benzene ring with a carbonyl side‑chain) satisfies the formula and IR data

About This Question

This is Neco 2021 Chemistry Question 34. It is one of the objective questions from the 2021 Neco Chemistry examination.

Difficulty level: Medium .

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