Match the structure in List - I with the coupling constant [¹H J(Hz)] given in List - II List - I (1) (2) (3)… · ABC26OR0709
Subject: Organic Chemistry · Chapter: Organic Spectroscopy · Topic: Organic Spectroscopy – General · Exam: GATE 2000-2022 · Marks: 2 · Difficulty: Easy
Match the structure in List - I with the coupling constant $[{}^{1}\mathrm{H}\ \mathrm{J(Hz)}]$ given in List - II List - I (1) 
(2) 
(3) 
List - II (i) ~ 1 Hz (ii) ~ 10 Hz (iii) ~ 15 Hz
(2) (3) List - II (i) ~ 1 Hz (ii) ~ 10 Hz (iii) ~ 15 Hz(a)1 - (i), 2 - (ii), 3 - (iii)
(b)1 - (ii), 2 - (iii), 3 - (i)
(d)1 - (iii), 2 - (i), 3 - (ii)
(c)1 - (iii), 2 - (ii), 3 - (i)
Answer
Answer: B ✓ checked by 4AB · confidence high
The source book printed A; on checking, B is correct — see the explanation.
In (1) the two H are cis (≈10 Hz), in (2) trans (≈15 Hz), and in (3) both H sit on the same carbon (geminal, ≈1 Hz). That gives 1-(ii), 2-(iii), 3-(i) = (b). The old key A treated (1) as geminal.
Explanation
(1) BrHC=CHCl with both H on the same side: cis vinyl coupling, ³J ≈ 10 Hz → (ii). (2) Both H on opposite sides: trans coupling, ³J ≈ 15 Hz → (iii). (3) BrClC=CH₂ has both H on one carbon: geminal sp² coupling, ²J ≈ 1 Hz → (i). Match: 1-(ii), 2-(iii), 3-(i). Answer: (b).
Study loop for Organic Spectroscopy