CUET · CHEMISTRY · PYQ PAPER 2025

An organic compound (A), C9H10O, gives a 2,4-DNP reaction, negative Tollens' test and iodoform test. On drastic oxidation with chromic acid, it forms B, having molecular formulae, C7H6O2. Identify A and B.

A A: 3-Phenylpropanal, B: Benzoic acid
B A: Propiophenone, B: Benzoic acid
C A: 1-Phenylacetophenone, B: Benzoic acid
D A: 3-Phenylpropanal, B: Phenylacetic acid

Verified Solution

Answer & Solution

Correct Answer

(B) A: Propiophenone, B: Benzoic acid

Step-by-step Solution

Detailed explanation

A is a ketone (2,4-DNP test positive, Tollens' test negative). A is not a methyl ketone (Iodoform test negative). A: Propiophenone, \( \text{C}_6\text{H}_5\text{COCH}_2\text{CH}_3 \) (C9H10O). B: Benzoic acid, \( \text{C}_6\text{H}_5\text{COOH} \) (C7H6O2).…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From CUET

Explore more questions on app

List-I	List-II
(A) k	(I) \(\frac{2}{15}\)
(B) \(P ( x =1)\)	(II) \(\frac{1}{5}\)
(C) \(P (1<x<3)\)	(III) \(\frac{8}{15}\)
(D) \(P(x \geq 2)\)	(IV) \(\frac{4}{15}\)