Coordination Compounds Chapter-Wise Test 6

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which pair exhibits linkage isomerism?

\( \ce{[Co(NH3)5SCN]^2+} \) and \( \ce{[Co(NH3)5NCS]^2+} \) differ by the binding atom of the ambidentate \( \ce{SCN^-} \) ligand (S vs. N), showing linkage isomerism.

\( \ce{[Co(NH3)6]^3+} \) and \( \ce{[Co(NH3)5Cl]^2+} \)
\( \ce{[Co(NH3)4Cl2]^+} \) (cis and trans)
\( \ce{[Co(NH3)5SO4]Br} \) and \( \ce{[Co(NH3)5Br]SO4} \)
\( \ce{[Co(NH3)5SCN]^2+} \) and \( \ce{[Co(NH3)5NCS]^2+} \)
4

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

\( \ce{[CoF6]^3-} \) (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.

\( \ce{[CoF6]^3-} \)
\( \ce{[Cr(H2O)6]^2+} \)
\( \ce{[Mn(CN)6]^3-} \)
\( \ce{[Fe(H2O)6]^3+} \)
3

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

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.

\( \Delta_t = \frac{2}{3} \Delta_o \)
\( \Delta_t = \Delta_o \)
\( \Delta_t = \frac{4}{9} \Delta_o \)
\( \Delta_t = \frac{9}{4} \Delta_o \)
3

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

\( \ce{[Co(CN)6]^3-} \) (Co\(^{3+}\), \( d^6 \)) with strong field \( \ce{CN^-} \) is low spin (\( t_{2g}^6 \)).

\( \ce{[Fe(H2O)6]^2+} \)
\( \ce{[CoF6]^3-} \)
\( \ce{[Co(CN)6]^3-} \)
\( \ce{[Fe(NH3)6]^2+} \)
3

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

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

1
3
0
4
2

Which complex is diamagnetic?

\( \ce{[Fe(CN)6]^3-} \) (Fe\(^{3+}\), \( d^5 \)) with strong field \( \ce{CN^-} \) in an octahedral field is low spin (\( t_{2g}^5 \)), but \( \ce{[Ni(CN)4]^2-} \) (Ni\(^{2+}\), \( d^8 \), square planar) has 0 unpaired electrons.

\( \ce{[Mn(H2O)6]^2+} \)
\( \ce{[Fe(H2O)6]^2+} \)
\( \ce{[Fe(CN)6]^3-} \)
\( \ce{[Ni(CN)4]^2-} \)
4

Which of the following is a homoleptic complex?

A homoleptic complex has only one type of ligand. \( \ce{[Co(NH3)6]^3+} \) has 6 \( \ce{NH3} \) ligands, making it homoleptic, unlike \( \ce{[Co(NH3)4Cl2]^+} \) with two ligand types.

\( \ce{[Co(NH3)4Cl2]^+} \)
\( \ce{[Co(NH3)6]^3+} \)
\( \ce{[Fe(H2O)5CN]^2+} \)
\( \ce{[Ni(NH3)2Cl2]} \)
2

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

In \( \ce{[Cr(NH3)4Cl2]^+} \), \( \ce{NH3} \) is neutral, each \( \ce{Cl^-} \) is -1. The complex charge is +1. Thus, \( x + 0 + 2(-1) = +1 \), so \( x = +3 \).

+2
+1
+3
+4
3

Which complex is diamagnetic?

\( \ce{[Co(CN)6]^3-} \) (Co\(^{3+}\), \( d^6 \)) with strong field \( \ce{CN^-} \) in an octahedral field is low spin (\( t_{2g}^6 \)), with 0 unpaired electrons, making it diamagnetic.

\( \ce{[Cr(NH3)6]^3+} \)
\( \ce{[Ni(NH3)6]^2+} \)
\( \ce{[CuCl4]^2-} \)
\( \ce{[Co(CN)6]^3-} \)
4

Which complex is diamagnetic?

\( \ce{[Fe(CN)6]^4-} \) (Fe\(^{2+}\), \( d^6 \)) with strong field \( \ce{CN^-} \) in an octahedral field is low spin (\( t_{2g}^6 \)), with 0 unpaired electrons.

\( \ce{[Cr(H2O)6]^3+} \)
\( \ce{[Ni(H2O)6]^2+} \)
\( \ce{[CoF6]^3-} \)
\( \ce{[Fe(CN)6]^4-} \)
4

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