Which one of the following reactions is correct?

1.  $\left[\mathrm{Fe}\right(\mathrm{CO}{)}_5]+2\mathrm{NO}\to \left[\mathrm{Fe}\right(\mathrm{CO}{)}_2\left(\mathrm{NO}{)}_2\right]+3\mathrm{CO}$

2.  $\left[\mathrm{Fe}\right(\mathrm{CO}{)}_5]+2\mathrm{NO}\to \left[\mathrm{Fe}\right(\mathrm{CO}{)}_3\left(\mathrm{NO}{)}_2\right]+2\mathrm{CO}$

3.  $\left[\mathrm{Fe}\right(\mathrm{CO}{)}_5]+3\mathrm{NO}\to \left[\mathrm{Fe}\right(\mathrm{CO}{)}_2\left(\mathrm{NO}{)}_3\right]+3\mathrm{CO}$

4. $\left[\mathrm{Fe}\right(\mathrm{CO}{)}_5]+3\mathrm{NO}\to \left[\mathrm{Fe}\right(\mathrm{CO}{)}_3\left(\mathrm{NO}{)}_3\right]+2\mathrm{CO}$

How many isomers are possible for complex [Co(Ox)₂Cl₂]^3-?

1.  1

2.  3

3.  2

4.  4

Which metal ion is present in Vitamin- B₁₂?

1. Zinc

2. Calcium

3. Iron

4. Cobalt

1. NO₃^- acts as a monodentate ligand.
2. The Ce atom has a coordination number of 12.
3. The shape of the complex ion is an icosahedron.
4. The solution is used as an oxidizing agent.

The metal carbonyl which is paramagnetic is:

The IUPAC name of [Co(ONO)(NH₃)₅]Cl₂ is: 

1.  Pentamminenitrocobalt(II)chloride

2.  Pentamminenitrsoocobalt(III)chloride  

3. Pentaaminenitrito-O-cobalt(III)chloride.  

4. Pentammineoxo-nitrocobalt(III)chloride

The total number of geometrical isomers possible for an octahedral complex of $\left[{\mathrm{MA}}_2{\mathrm{B}}_2{\mathrm{C}}_2\right]$ are:
(M = transition metal; A, B and C are monodentate ligands)

Hybridization and geometry of ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$ are

1.  $s{p}^{2}d$ and tetrahedral

2.  $s{p}^3$ and square planar

3.  $s{p}^3$ and tetrahedral

4.  $ds{p}^2$ and square planar

Among the following complexes, the one that can exist
as facial(fac) and meridional(mer) isomer is: