Medium MCQ +4 / -1 PYQ · JEE Mains 2023

Match List I with List II

LIST I
Coordination Complex
LIST II
Number of unpaired electrons
A. $\left[\mathrm{Cr}(\mathrm{CN})_{6}\right]^{3-}$ I. 0
B. $\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ II. 3
C. $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$ III. 2
D. $\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{6}\right]^{2+}$ IV. 4

Choose the correct answer from the options given below:

  1. A A-IV, B-III, C-II, D-I
  2. B A-II, B-I, C-IV, D-III
  3. C A-II, B-IV, C-I, D-III Correct answer
  4. D A-III, B-IV, C-I, D-II

Solution

For option (A)<br/><br/> $$ \begin{aligned} & \mathrm{Cr}^{+3}: 3 \mathrm{~d}^3 \\\\ & \mathrm{CN}^{-} \rightarrow \mathrm{SFL} \end{aligned} $$<br/><br/> No. of unpaired electrons $=3$<br/><br/> For option (B)<br/><br/> $$ \begin{aligned} & \mathrm{Fe}^{+2}: 3 \mathrm{~d}^6 \\\\ & \mathrm{H}_2 \mathrm{O}: \mathrm{WFL} \end{aligned} $$<br/><br/> No. of unpaired electrons $=4$<br/><br/> For option (C)<br/><br/> $$ \begin{aligned} & \mathrm{Co}^{+3}: 3 \mathrm{~d}^6 \\\\ & \mathrm{NH}_3: \mathrm{SFL} \end{aligned} $$<br/><br/> No. of unpaired electrons $=0$<br/><br/> For option (D)<br/><br/> $$ \begin{aligned} & \mathrm{Ni}^{+2}: 3 \mathrm{~d}^8 \\\\ & \mathrm{NH}_3: \mathrm{SFL} \end{aligned} $$<br/><br/> No. of unpaired electrons $=2$

About this question

Subject: Chemistry · Chapter: Coordination Compounds · Topic: Ligands and Coordination Number

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