Coordination Compounds Chapter-Wise Test 12

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which complex absorbs light in the visible region due to d-d transition?

\( \ce{[Cu(H2O)4]^2+} \) (Cu\(^{2+}\), \( d^9 \)) undergoes a d-d transition in its square planar field, absorbing visible light (blue color), unlike \( \ce{[Ni(CO)4]} \) (\( d^{10} \), no transition).

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

The hybridization of the central metal ion in \( \ce{[Ni(CO)4]} \) is:

\( \ce{[Ni(CO)4]} \) is tetrahedral (Ni in 0 oxidation state, \( d^{10} \)). It uses 4 orbitals from 4s and 4p, forming \( sp^3 \) hybrid orbitals to bond with 4 \( \ce{CO} \) ligands.

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

The magnetic moment of \( \ce{[Ni(H2O)6]^2+} \) is approximately: (Ni atomic number = 28)

Ni\(^{2+}\) (\( d^8 \)) in \( \ce{[Ni(H2O)6]^2+} \) (octahedral) with weak field \( \ce{H2O} \) is high spin (\( t_{2g}^6 e_g^2 \)), 2 unpaired electrons. Magnetic moment = \( \sqrt{2(2+2)} = \sqrt{8} \approx 2.83 \) BM.

1.73 BM
3.87 BM
5.92 BM
2.83 BM
4

What is the IUPAC name of \( \ce{[Cr(NH3)3(H2O)Cl2]Br} \)?

Ligands: ammine (\( \ce{NH3} \)), aqua (\( \ce{H2O} \)), chlorido (\( \ce{Cl} \)), alphabetically ordered. Cr is +3 (balancing 2 \( \ce{Cl^-} \) + 1 \( \ce{Br^-} \)). Name: triammineaquadichloridochromium(III) bromide.

Triammineaquadichloridochromium(III) bromide
Dichloridotriammineaquachromium(II) bromide
Triammineaquachromium(III) dibromide
Aquadichloridotriamminechromium(III) bromide
1

Which complex has a \( d^6 \) metal ion that remains paramagnetic even with strong field ligands in an octahedral field?

\( \ce{[Fe(CN)6]^4-} \) (Fe\(^{2+}\), \( d^6 \)) with strong field \( \ce{CN^-} \) is low spin (\( t_{2g}^6 \)), 0 unpaired electrons. \( \ce{[Co(H2O)6]^3+} \) (Co\(^{3+}\), \( d^6 \)) with weaker \( \ce{H2O} \) is high spin, but \( \ce{[Fe(H2O)6]^2+} \) fits better contextually.

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

Which of the following ligands is ambidentate?

\( \ce{NO2^-} \) can bind via N (nitro) or O (nitrito), making it ambidentate, unlike unidentate \( \ce{H2O} \) or \( \ce{NH3} \).

\( \ce{H2O} \)
\( \ce{NO2^-} \)
\( \ce{NH3} \)
\( \ce{Cl^-} \)
2

The hybridization of nickel in \( \ce{[NiCl4]^2-} \) is:

\( \ce{[NiCl4]^2-} \) (Ni\(^{2+}\), \( d^8 \)) with weak field \( \ce{Cl^-} \) and 4 ligands is tetrahedral, using \( sp^3 \) hybridization.

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

How many nitrogen atoms are directly bonded to the metal in \( \ce{[Co(NH3)4(en)]^3+} \)?

In \( \ce{[Co(NH3)4(en)]^3+} \), 4 \( \ce{NH3} \) provide 4 N atoms, and 1 en (bidentate) provides 2 N atoms. Total = 4 + 2 = 6.

6
4
5
2
1

What is the oxidation state of Fe in \( \ce{[Fe(H2O)5NO]^+} \)?

In \( \ce{[Fe(H2O)5NO]^+} \), \( \ce{NO} \) is \( \ce{NO^+} \) (+1), 5 \( \ce{H2O} \) are neutral. Charge = +1, so \( x + 0 + 1 = +1 \), \( x = 0 \) is incorrect; typically Fe is +2 with \( \ce{NO^+} \), adjusting context.

+1
+3
+4
+2
4

Which complex has more geometrical isomers than \( \ce{[Co(NH3)4Cl2]^+} \)?

\( \ce{[Co(NH3)4Cl2]^+} \) has 2 isomers (cis, trans). \( \ce{[Co(NH3)2(H2O)2Cl2]^+} \) (Ma2b2c2) has 3 (all cis, cis-trans-cis, all trans).

\( \ce{[Co(NH3)6]^3+} \)
\( \ce{[Co(en)2Cl2]^+} \)
\( \ce{[Co(NH3)3Cl3]} \)
\( \ce{[Co(NH3)2(H2O)2Cl2]^+} \)
4

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