Coordination Compounds Chapter-Wise Test 17

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which complex has a tetrahedral geometry and is paramagnetic?

\( \ce{[CoCl4]^2-} \) (Co\(^{2+}\), \( d^7 \)) with weak field \( \ce{Cl^-} \) is tetrahedral and high spin (3 unpaired electrons), making it paramagnetic.

\( \ce{[Ni(CN)4]^2-} \)
\( \ce{[CuCl4]^2-} \)
\( \ce{[Ni(NH3)4]^2+} \)
\( \ce{[CoCl4]^2-} \)
4

How many unpaired electrons are present in \( \ce{[Ni(NH3)6]^2+} \)? (Ni atomic number = 28)

Ni\(^{2+}\) (\( d^8 \)) in \( \ce{[Ni(NH3)6]^2+} \) (octahedral) with \( \ce{NH3} \) (moderate field) is high spin: \( t_{2g}^6 e_g^2 \), giving 2 unpaired electrons.

0
1
3
2
4

Which complex can exist as a pair of enantiomers?

\( \ce{[Co(en)3]^3+} \) (octahedral) with 3 bidentate en ligands lacks symmetry, forming non-superimposable mirror images (enantiomers).

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

The EAN of Ni in \( \ce{[Ni(en)2]^2+} \) is: (Ni atomic number = 28)

Ni\(^{2+}\) with 2 en ligands (4 donor atoms). EAN = 28 - 2 + 2 × 4 = 34.

36
32
34
38
3

Which complex is colored due to a d-d transition?

\( \ce{[Ni(H2O)6]^2+} \) (Ni\(^{2+}\), \( d^8 \)) in an octahedral field undergoes d-d transitions, absorbing visible light (green color).

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

The magnetic moment of \( \ce{[FeF6]^3-} \) is approximately: (Fe atomic number = 26)

Fe\(^{3+}\) (\( d^5 \)) in \( \ce{[FeF6]^3-} \) (octahedral) with weak field \( \ce{F^-} \) is high spin (5 unpaired electrons). Magnetic moment = \( \sqrt{5(5+2)} = \sqrt{35} \approx 5.92 \) BM.

1.73 BM
3.87 BM
4.90 BM
5.92 BM
4

The hybridization of iron in \( \ce{[Fe(H2O)6]^2+} \) is:

\( \ce{[Fe(H2O)6]^2+} \) (Fe\(^{2+}\), \( d^6 \)) is octahedral with weak field \( \ce{H2O} \), forming a high-spin complex with outer orbitals (\( sp^3d^2 \)).

\( d^2sp^3 \)
\( sp^3d^2 \)
\( sp^3 \)
\( dsp^2 \)
2

How many moles of \( \ce{AgCl} \) precipitate when 1 mole of \( \ce{[Cr(NH3)4Cl2]Cl} \) reacts with excess \( \ce{AgNO3} \)?

In \( \ce{[Cr(NH3)4Cl2]Cl} \), 1 \( \ce{Cl^-} \) outside the coordination sphere is ionizable, forming 1 mole of \( \ce{AgCl} \).

2
3
1
0
3

What is the primary valence of Fe in \( \ce{[Fe(H2O)6]SO4} \)?

Primary valence is the oxidation state. In \( \ce{[Fe(H2O)6]SO4} \), \( \ce{H2O} \) is neutral, \( \ce{SO4^2-} \) is -2, balanced by \( \ce{[Fe(H2O)6]^2+} \), so Fe is +2.

3
1
2
4
3

What is the primary valence of Co in \( \ce{[CoCl2(NH3)4]Cl} \)?

Primary valence is the oxidation state. In \( \ce{[CoCl2(NH3)4]Cl} \), the complex \( \ce{[CoCl2(NH3)4]^+} \) has a +1 charge (balanced by 1 \( \ce{Cl^-} \)). \( \ce{NH3} \) is neutral, \( \ce{Cl^-} \) is -1. Thus, Co’s oxidation state = +3 (since +3 + 2(-1) = +1).

2
1
4
3
4

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