NEET Coordination Compounds — Set 6

Question 1

How many unpaired electrons are present in $ \ce{[Cr(NH3)6]^3+} $? (Cr atomic number = 24)

Accepted Answer

Cr$^{3+}$ ($ d^3 $) in $ \ce{[Cr(NH3)6]^3+} $ (octahedral) with $ \ce{NH3} $ (moderate field) has $ t_{2g}^3 $, giving 3 unpaired electrons.

Question 2

The crystal field splitting energy ($ \Delta_t $) in a tetrahedral field is related to $ \Delta_o $ (octahedral) by:

Accepted Answer

For the same metal and ligands, the tetrahedral splitting $ \Delta_t = \frac{4}{9} \Delta_o $, due to fewer ligands and different geometry causing less repulsion.

Question 3

Which complex has a $ d^4 $ metal ion with 2 unpaired electrons in an octahedral field?

Accepted Answer

$ \ce{[CoF6]^3-} $ (Co$^{3+}$, $ d^6 $) is incorrect; $ \ce{[Cr(H2O)6]^2+} $ (Cr$^{2+}$, $ d^4 $) with weak field $ \ce{H2O} $ is high spin ($ t_{2g}^3 e_g^1 $), but $ \ce{[Mn(CN)6]^3-} $ (Mn$^{3+}$, $ d^4 $) with strong field $ \ce{CN^-} $ is low spin ($ t_{2g}^4 $), 2 unpaired electrons.

NEET Chemistry: Coordination Compounds — Practice Set 6

Q1. How many unpaired electrons are present in \( \ce{[Cr(NH3)6]^3+} \)? (Cr atomic number = 24)

Q2. The crystal field splitting energy (\( \Delta_t \)) in a tetrahedral field is related to \( \Delta_o \) (octahedral) by:

Q3. Which complex has a \( d^4 \) metal ion with 2 unpaired electrons in an octahedral field?

Q4. What is the oxidation state of chromium in \( \ce{[Cr(NH3)4Cl2]^+} \)?

Q5. Which complex is diamagnetic?

Q6. Which complex is diamagnetic?

Q7. Which of the following is a homoleptic complex?

Q8. Which complex has a \( d^6 \) metal ion that is low spin in an octahedral field?

Q9. Which complex is diamagnetic?

Q10. Which pair exhibits linkage isomerism?