JEE Main 2026 — Apr 4, Shift 1 — Chemistry solution

JEE Main2026Apr 4, Shift 1Chemistry

Match the List-I with List-II

List-I (Complex ion)	List-II (Calculated spin only magnetic moment (BM))
A. $[Cr (H_{2} O)_{6}]^{2 +}$	I. $3.87$
B. $[Co (H_{2} O)_{6}]^{2 +}$	II. $5.92$
C. $[Cu (H_{2} O)_{6}]^{2 +}$	III. $4.90$
D. $[Mn (H_{2} O)_{6}]^{2 +}$	IV. $1.73$

Choose the correct answer from the options given below:

Solution

$H_{2} O$ is a weak field ligand, so all complexes are high-spin. Use $μ = n (n + 2)$ BM where $n$ is the number of unpaired electrons.

A. $C r^{2 +}$ : $d^{4} \Rightarrow n = 4 \Rightarrow μ = 24 \approx 4.90$ BM (III).

B. $C o^{2 +}$ : $d^{7} \Rightarrow n = 3 \Rightarrow μ = 15 \approx 3.87$ BM (I).

C. $C u^{2 +}$ : $d^{9} \Rightarrow n = 1 \Rightarrow μ = 3 \approx 1.73$ BM (IV).

D. $M n^{2 +}$ : $d^{5} \Rightarrow n = 5 \Rightarrow μ = 35 \approx 5.92$ BM (II).

Matching: A-III, B-I, C-IV, D-II.

Practice more Chemistry

Concept-wise practice with instant solutions on Fundamenthol.