Q45. The product (X) is:
R-CH=CH-CHO + NH2-C-NH-NH2 → X (image of reaction: alpha,beta-unsaturated a

Q: What is the correct answer for CUET UG Chemistry Q45?

The correct answer is B. The reaction shown is the condensation of an aldehyde (R-CH=CH-CHO, an α,β-unsaturated aldehyde) with semicarbazide (NH2-NH-CO-NH2) to form a semicarbazone. In semicarbazide, the terminal -NH2 group (farthest from the carbonyl group) is more nucleophilic because the other -NH2 group's lone pair is involved in resonance with the adjacent carbonyl, making it less available for nucleophilic attack.Th

Q: Q45. The product (X) is: R-CH=CH-CHO + NH2-C-NH-NH2 → X (image of reaction: alpha,beta-unsaturated aldehyde + semicarbazide -> product X) (a) R-CH=CH-CH=CH-NH-NH2 (b) R-CH=CH-CH=N-C-NH-NH2 (c)…

The correct answer is B. The reaction shown is the condensation of an aldehyde (R-CH=CH-CHO, an α,β-unsaturated aldehyde) with semicarbazide (NH2-NH-CO-NH2) to form a semicarbazone. In semicarbazide, the terminal -NH2 group (farthest from the carbonyl group) is more nucleophilic because the other -NH2 group's lone pair is involved in resonance with the adjacent carbonyl, making it less available for nucleophilic attack.Th

Q: What are the options for this CUET UG Chemistry question?

A. (a) R-CH=CH-CH=CH-NH-NH2 · B. (b) R-CH=CH-CH=N-C-NH-NH2 · C. (c) R-CH2-C-CH=N-NH-C-NH2 · D. (d) R-CH=CH-CH=N-NH-C-NH2

Question

Q45. The product (X) is:
R-CH=CH-CHO + NH2-C-NH-NH2 → X (image of reaction: alpha,beta-unsaturated aldehyde + semicarbazide -> product X)
(a) R-CH=CH-CH=CH-NH-NH2
(b) R-CH=CH-CH=N-C-NH-NH2
(c) R-CH2-C-CH=N-NH-C-NH2
(d) R-CH=CH-CH=N-NH-C-NH2

FirstInTest · Accepted Answer

The reaction shown is the condensation of an aldehyde (R-CH=CH-CHO, an α,β-unsaturated aldehyde) with semicarbazide (NH2-NH-CO-NH2) to form a semicarbazone. In semicarbazide, the terminal -NH2 group (farthest from the carbonyl group) is more nucleophilic because the other -NH2 group's lone pair is involved in resonance with the adjacent carbonyl, making it less available for nucleophilic attack.The reaction involves the elimination of a water molecule between the carbonyl oxygen of the aldehyde and the two hydrogens of the more nucleophilic amino group of semicarbazide.R-CH=CH-CHO + H2N-NH-CO-NH2 → R-CH=CH-CH=N-NH-CO-NH2 + H2OTherefore, the product formed is R-CH=CH-CH=N-NH-CO-NH2. Both options (b) and (d) depict this structure. Given option (b) is the correct answer, it implies (b) is the intended representation.

Answer

(a) R-CH=CH-CH=CH-NH-NH2

Answer

(b) R-CH=CH-CH=N-C-NH-NH2

Answer

(c) R-CH2-C-CH=N-NH-C-NH2

Answer

(d) R-CH=CH-CH=N-NH-C-NH2

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