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JEE Advanced Chemistry Coordination Compounds 2021 JEE Advanced 2021 (Paper 1)

JEE Advanced Chemistry Question (2021) — Solution

Question

The calculated spin only magnetic moments of  Cr NH 3 6 3 +  and  CuF 6 3 -  in  BM ,  respectively, are (Atomic numbers of Cr and Cu are 24 and 29 , respectively)

Options

  1. A. 3 . 87  and  2 . 84
  2. B. 4 . 90  and  1 . 73
  3. C. 3 . 87  and  1 . 73
  4. D. 4 . 90  and  2 . 84

Answer

A. 3 . 87  and  2 . 84

Step-by-step solution

Spin only magnetic moment can be calculated using the formula  μ = n   n + 2   B . M n =  number of unpaired electron at central atom. Cr NH 3 6 3 +  :  Cr 3 +  is the central metal ion. Cr 3 +  :  3 d 3  configuration  It has three unpaired electrons. μ = 3 3 + 2   BM = 3 .87   BM CuF 6 3 −  :  Cu 3 +  is the central metal ion. Cu 3 +  :  3 d 8  configuration Fluorine is the weak field ligand. Its electronic configuration is  t 2 g 6   e g 2 . Hence, it has two unpaired electrons. μ = 2 2 + 2   BM = 2 .84 BM

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