Chemistry

Coordination Compounds

Question:

Assertion (A): Complexes of MX6 and MX5L type (X and L are unidentate) do not show geometrical isomerism.
Reason (R): Geometrical isomerism is not shown by complexes of coordination number 6.

Answer:

(c) For complexes of MX6 and MX5L type, different geometric arrangements of the ligands is not possible.
MA4B2, M(AA)2B2  and MA3B3 type of complexes are the complexes with coordination number 6 which show geometrical isomerism.

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Coordination Compounds

Q 1.

When 1 mol CrCl3.6H2O is treated with excess of AgNO3, 3 mol of AgCl are obtained. The formula of the complex is
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-6

Q 2.

What is meant by unidentate didentate and ambidentate ligands? Give two examples for each.

Q 3.

Assertion (A): [Cr(H2O)6]Cl2 and [Fe(H2O)6]Cl2 are reducing in nature. Reason (R): Unpaired electrons are present in their J-orbitals.

Q 4.

Calculate the overall complex dissociation equilibrium constant for the  Cu(NH3)42+  ion, given that β4  for this complex is 2.1 x  1013.

Q 5.

Write the IUPAC names of the following coordination compounds:
(i)[Co(NH3)6]Cl3
(ii)[Co(NH3)5Cl]Cl2
(iii)K3[Fe(CN)6l
(iv)K3lFe(C2O4)3]
(v)K2[PdCl4]
(vi)[Pt(NH3)2Cl(NH2CH3)]Cl

Q 6.

On the basis of crystal field theory explain why Co(III) forms paramagnetic octahedral complex with weak field ligands whereas it forms diamagnetic octahedral complex with strong field ligands.

Q 7.

A complex of the type [M(AA)2X2]n+ is known to be optically active. What does this indicate about the structure of the complex? Give one example of such complex.

Q 8.

[Fe(CN)6]4- and [Fe(H2O)6]2+ are of different cdlours in dilute solutions. Why?

Q 9.

The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-3

Q 10.

Which of the following options are correct for [Fe(CN)6]3- complex?
(a) d2sp3 hybridisation
(b) sp3d2  hybridisation
(c) Paramagnetic
(d) Diamagnetic

Q 11.

Magnetic moment of [MnCl4]2- is 5.92 BM. Explain giving reason.

Q 12.

In the following questions, a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the following choices.
(a) Assertion and Reason both are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason both are true but Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Assertion is false, Reason is true.

Assertion (A): Toxic metal ions are removed by the chelating ligands. Reason (R): Chelate complexes tend to be more stable.

Q 13.

Match the complex species given in Column I with the possible isomerism given in Column II and assign the correct code:
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-32

Q 14.

Discuss the nature of bonding in metal carbonyls.

Q 15.

Why do compounds having similar geometry have different magnetic moment?

Q 16.

What is meant by stability of a coordination compound in solution? State the factors which govern stability of complexes.

Q 17.

Arrange following complex ions in increasing order of crystal field splitting energy (A0):
[Cr(Cl)6]3-, [Cr(CN)6]3-, [Cr(NH3)6]3+

Q 18.

Explain on the basis of valence bond theory that  [Ni(CN)4]2-  ion with square planar structure is diamagnetic and the[Ni(CN)4]2- ion with tetrahedral geometry is paramagnetic.

Q 19.

What is meant by the chelate effect? Give an example.

Q 20.

What will be the correct order for the wavelengths of absorption in the visible region for the following:[Ni(NO2)6]4-, [Ni(NH3)6]2+, [Ni(H20)6]2+?

Q 21.

The stabilization of coordination compounds due to chelation is called the chelate effect. Which of the following is the most stable complex species?
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-7

Q 22.

Match the coordination compounds given in Column I with the central metal atoms given in Column II and assign the correct code:
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-27
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-28

Q 23.

What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex?

Q 24.

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

Q 25.

Draw all the isomers (geometrical and optical) of
(i)[CoCl2(en)2]+
(ii)[Co(NH3) Cl (en)2]2+
(iii) [Co(NH3)2Cl2(en)]+

Q 26.

How many ions are produced from the complex Co(NH3)6Cl2 in solution?
(i) 6
(ii) 4
(iii)3
(iv)2

Q 27.

Why are low spin tetrahedral complexes not formed?

Q 28.

Give evidence that  [Co(NH3)5Cl]S04  and [Co(NH3)5S04]Cl  are ionisation isomers.

Q 29.

Specify the oxidation numbers of the metals in the following coordination entities:
(i) [Co(H2O)(CN)(en)2]2+ (ii) [CoBr2(en)2]+ (iii) [PtCl4]2-  (iv) K3[Fe(CN)6] (v) [Cr(NH3)3CI3]

Q 30.

Write all the geometrical isomers of [Pt(NH3)(Br)(Cl) (Py)] and how many of these will exhibit optical isomerism?

Q 31.

Which of the following complexes show linkage isomerism?
(a) [CO(NH3)5(NO2)]2+  (b) [CO(H2O)5CO]3+
(c) [Cr(NH3)5SCN]2+  (d) [Fe(en)2Cl2]+

Q 32.

Arrange the following complexes in the increasing order of conductivity of their solution:
[Co(NH3)3Cl3], [CO(NH3)4Cl2]Cl, [CO(NH3)6]C13, [Cr(NH3)5Cl]Cl2

Q 33.

Give the electronic configuration of the following complexes on the basis of crystal field splitting theory.
[COF6]3-, [Fe(CN)6]4- and [Cu(NH3)6]2+.

Q 34.

CUSO4.5H2O is blue in colour while CuSO4 is colourless. Why?

Q 35.

Write the formulas for the following coordination compounds:
(i)Tetraamminediaquacobalt(IlI) chloride
(ii)Potassium tetracyanidonickelate(II)
(iii)Tris(ethanp-1,2-diamine) chromium(III) chloride
(iv)Amminebromidochloridonitrito-N- platinatc(II)
(v)Dichloridobis(ethane-l ,2-diamine) platinum (IV) nitrate
(vi)Iron(III)hexacyanidoferrate(II)

Q 36.

How many geometrical isomers are possible in . the following coordination entities?
(i) [Cr(C2O4)3]3- (ii) [CoCl3(NH3)3]

Q 37.

Draw the structures of optical isomers of
(i) [Cr(C2O4)3]3-
(ii)[PtCI2(en)2]2+
(iii)[Cr(NH3)2CI2(en)]+

Q 38.

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.

Q 39.

What is crystal field splitting energy? How does the magnitude of Δ0 decide the actual configuration of d-orbitals in a coordination entity?

Q 40.

Which of the following complexes are homoleptic?
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-16

Q 41.

Which of the following complexes are heteroleptic?
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-17

Q 42.

Explain why [Fe(H2O)6]3+  has magnetic moment value of 5.92 BM whereas [Fe(CN)6]3- has a value of only 1.74 BM.

Q 43.

Match the complex ions given in Column I with the colours given in Column II and assign the correct code:
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-26

Q 44.

Assertion (A): (Fe(CN)6]3-  ion shows magnetic moment corresponding to two unpaired electrons.
Reason (R): Because it has d2sp3  type hybridisation.

Q 45.

CoSO4Cl.5NH3 exists in two isomeric forms ‘A' and ‘B'. Isomer ‘A' reacts with AgNO3 to give white precipitate, but does not react with BaCl2. Isomer ‘B' gives white precipitate with BaCl2 but does not react with AgNO3. Answer the following questions.
(i) Identify A' and B' and write their structural formulas.
(ii) Name the type of isomerism involved.
(iii) Give the IUPAC name of A' and B'.

Q 46.

Using IUPAC norms write the formulas for the following:
(i)Tetrahydroxozincate(Il)
(ii)Potassium tetrachloridopalladate (II)
(iii)Diamminedichlorido platinum (II)
(iv)Potassium tetracyanonickelate (II)
(v)Pentaamminenitrito-O-cobalt(III)
(vi)Ilexaamminccobalt (III) sulphate
(vii)Potassium tri(oxalato) chromate (III)
(yiii)Hexaammineplatinum (IV)
(ix)Tetrabromidocuprate(II)
(x) Pentaamminenitrito-N-cobalt (III)

Q 47.

A solution of [Ni(H20)6]2+ is green but a solution of [Ni(CN)4]2-is colourless. Explain.

Q 48.

Discuss briefly giving an example in each case the role of coordination compounds in:(i)biological systems (iii) analytical chemistry (ii)medicinal chemistry and (iv) extraction/ metallurgy of metals.

Q 49.

Which of the following complex formed by Cu2+ ions is most stable?
ncert-exemplar-problems-class-12-chemistry-coordination-compounds-1

Q 50.

A coordination compound CrCl3.4H2O precipitates silver chloride when treated with silver nitrate. The molar conductance of its solution corresponds to a total of two ions. Write structural formula of the compound and name it.