Which of the following has the longest C ­—O bond length? (Free C—O bond length in CO is 1.128 Å)

1. [Co(CO)₄]^-
2. [Fe(CO)₄]^2-
3. Mn(CO)₆]⁺
4. Ni(CO)₄

The number of possible isomers for the complex $\left[\mathrm{Co}{\left(\mathrm{en}\right)}_2{\mathrm{Cl}}_2\right]Cl$ will be (en=ethylenediamine):

1. 2

2. 1

3. 3

4. 4

The hybridization involved in the complex ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$is:
(Atomic number of Ni=28)

1. $ds{p}^2$

2. $s{p}^3$

3. $d^{2}s{p}^2$

4. $d^{2}s{p}^3$

The sum of the coordination number and oxidation number of the metal M in the complex [M(en)₂(C₂O₄)]Cl is:

The IUPAC name of complex ion, [Fe(CN)₆]^3- is:

1. Hexacyanoiron(III) ion

2. Hexacyanitoferrate(III) ion

3. Tricynoferrate(III) ion

4. Hexacyanidoferrate(III) ion

An ion, among the following, that has a magnetic moment of 2.84 BM is:
(At. no. Ni = 28, Ti = 22, Cr = 24, Co = 27)

1. Ni²⁺
2. Ti³⁺
3. Cr²⁺
4. Co²⁺

Cobalt(III) chloride forms several octahedral complexes with ammonia.
A compound among the following that does not give a test for chloride ions with silver nitrate at 25 °C is:

An anticancer agent among the following is:

1. $\mathrm{mer}-\left[\mathrm{Co}\right({\mathrm{NH}}_3{)}_3\mathrm{Cl}]$

2. c$\mathrm{is}-\left[{\mathrm{PtCl}}_2\right({\mathrm{NH}}_3{)}_2]$

3. c$\mathrm{is}-{\mathrm{K}}_2[\mathrm{Pt}$ ${\mathrm{Cl}}_2{\mathrm{Br}}_2]$

4. ${\mathrm{NH}}_2{\mathrm{CoCl}}_4$

The complexes [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆] show:

1. Ionisation isomerism

2. Co-ordination isomerism

3. Geometrical isomerism

4. Linkage isomerism