List of top Chemistry Questions on Coordination Compounds asked in CBSE CLASS XII

Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:
\((i) K[Cr(H_2O)_2(C_2O_4)_2].3H_2O\)
\((ii)[Co(NH_3)_5Cl]Cl_2\)
\((iii) CrCl_3(py)_3\)
\((iv) Cs[FeCl_4]\)
\((v)K_4[Mn(CN)_6]\)

Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory: 
\((i) [Fe(CN)_6]^{4-} \)
\((ii) [FeF_6]^{3-}\)
\((iii) [Co(C_2O_4)_3]^{3-} \)
\((iv) [CoF_6]^{3-}\)

Amongst the following ions which one has the highest magnetic moment value? 
(i) \([Cr(H_2O)_6]^{3+}\)
(ii) \([Fe(H_2O)_6]^{2+} \)
(iii)\( [Zn(H_2O)_6]^{2+}\)

\([Cr(NH_3)_6]^{3+}\) is paramagnetic while \([Ni(CN)_4]^{2-}\) is diamagnetic. Explain why?

What is meant by the chelate effect? Give an example
What is meant by stability of a coordination compound in solution? State the factors which govern stability of complexes.

Give the oxidation state, d-orbital occupation and coordination number of the central metal ion in the following complexes: 
(i) \(K_3[Co(C_2O_4)_3] \)
(ii)\( cis-[Cr(en)_2Cl_2]Cl \)
(iii) \((NH_4)_2[CoF_4] \)
(iv) \([Mn(H_2O)_6]SO_4\)

\([Fe(CN)_6]^{4-}\) and \([Fe(H_2O)_6]^{2+}\) are of different colours in dilute solutions. Why?

A solution of \([Ni(H_2O)_6]^{2+}\) is green but a solution of \([Ni(CN)_4]^{2-}\) is colourless. Explain.

What is crystal field splitting energy? How does the magnitude of\( Δo\) decide the actual configuration of d-orbitals in a coordination entity?

Draw figure to show the splitting of d orbitals in an octahedral crystal field.
Aqueous copper sulphate solution (blue in colour) gives:
(i) a green precipitate with aqueous potassium fluoride, and
(ii) a bright green solution with aqueous potassium chloride Explain these experimental results.

How many geometrical isomers are possible in the following coordination entities? 
(i)\( [Cr(C_2O_4)_3]^{ 3–} \)
(ii)\( [Co(NH_3)_3Cl_3]\)

Using IUPAC norms write the systematic names of the following: 
(i)\( [Co(NH_3)_6]Cl_3 \)
(ii) \([Pt(NH_3)_2Cl(NH_2CH_3)]Cl \)
(iii) \([Ti(H_2O)_6]^{3+} \)
(iv) \([Co(NH_3)_4Cl(NO_2)]Cl \)
(v)\( [Mn(H_2O)_6]^{2+}  \)
(vi) \([NiCl_4]^{2–}\)
(vii) \([Ni(NH_3)_6]Cl_2   \)
(viii) \([Co(en)_3]^{3+} \) 
(ix)\( [Ni(CO)_4]\)
Using IUPAC norms write the formulas for the following: 
(i) Tetrahydroxidozincate(II) 
(ii) Potassium tetrachloridopalladate(II) 
(iii) Diamminedichloridoplatinum(II) 
(iv) Potassium tetracyanidonickelate(II) 
(v) Pentaamminenitrito-O-cobalt(III)
(vi) Hexaamminecobalt(III) sulphate ) 
(vii) Potassium tri(oxalato)chromate(III)  
(viii) Hexaammineplatinum(IV)  
(ix) Tetrabromidocuprate(II)  
(x) Pentaamminenitrito-N-cobalt(III)

Specify the oxidation numbers of the metals in the following coordination entities: 
(i)\( [Co(H_2O)(CN)(en)_2] ^{2+}\)
(ii) \([CoBr_2(en)_2]^{+}\)
(iii)\( [PtCl_4]^{ 2–} \)
(iv) \(K_3[Fe(CN)_6]\)
(v) \([Cr(NH_3)_3Cl_3] \)

What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.
Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.

\(FeSO_4\) solution mixed with\( (NH_4)_2SO_4 \) solution in\( 1:1\) molar ratio gives the test of \(Fe^{2+}\) ion but \(CuSO_4\) solution mixed with aqueous ammonia in \( 1:4 \) molar ratio does not give the test of \(Cu^{2+}\) ion. Explain why?

Explain the bonding in coordination compounds in terms of Werner’s postulates.