The CFSE for $\left[\right(\mathrm{Cocl}{)}_6{]}^{4-}$ complex is 18000 ${\mathrm{cm}}^{-1}$. The $∆$ for $\left[\right(\mathrm{Cocl}{)}_4{]}^{2-}$ will be:

(a) 18000 ${\mathrm{cm}}^{-1}$                    (b) 16000 ${\mathrm{cm}}^{-1}$

(c) 8000 ${\mathrm{cm}}^{-1}$                       (d) 2000 ${\mathrm{cm}}^{-1}$

Which of the following order of CFSE is incorrect?

$\left(\mathrm{a}\right) \left[\mathrm{Co}\right(\mathrm{en}{)}_3{]}^{3+ }>\left[\mathrm{Co}\right({\mathrm{NH}}_3{)}_6{]}^{3+}>\left[\mathrm{Co}\right({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{3+}$

(b) $[{\mathrm{PtCl}}_4{]}^{2-}>[{\mathrm{PdCl}}_4{]}^{2-}>[{\mathrm{NiCl}}_4{]}^{2-}$

(c) $\left[\mathrm{Ni}\right(\mathrm{dmgH}{)}_2]<[\mathrm{Ni}(\mathrm{en}{)}_2{]}^{2+}$

(d) $\left[\mathrm{Co}\right(\mathrm{ox}{)}_3{]}^{3-}<\left[\mathrm{Co}\right(\mathrm{en}{)}_3{]}^{3+}$

For which of the following ${\mathrm{d}}^{\mathrm{n}}$ configuration of octahedral complexes, can not exist in both high spin and slow spin forms:

(I) ${\mathrm{d}}^3$                  (II) ${\mathrm{d}}^5$               (III) ${\mathrm{d}}^6$             (IV) ${\mathrm{d}}^8$

(1) I,II and III                                 

(2) II,III & IV

(3) I & IV                                         

(4) None of these

Consider the complex $\left[\mathrm{Co}\right({\mathrm{NH}}_3{)}_4{\mathrm{CO}}_3]{\mathrm{ClO}}_4$ , in which coordination number, oxidation number and number of d-electrons on the metal are respectively.

(1) 6,3,6       

(2) 6,2,7     

(3) 5,3,6     

(4) 5,3,7

The $\mathrm{\pi }$-ligand which uses its d-orbital during synergic bonding in its complex compound.

(1) ${\mathrm{CN}}^{-}$   

(2) ${\mathrm{PR}}_3$     

(3) $\mathrm{NO}$     

(4) ${\mathrm{N}}_2$

The IR stretchin frequencies of free CO, and CO in $\left[\mathrm{V}\right(\mathrm{CO}{)}_6{]}^{-} , \left[\mathrm{Cr}\right(\mathrm{CO}{)}_6{]}^{} \mathrm{and} \left[\mathrm{Mn}\right(\mathrm{CO}{)}_6{]}^{+}$ are 2143 ${\mathrm{cm}}^{-1}$, 1860 ${\mathrm{cm}}^{-1}$,2000 ${\mathrm{cm}}^{-1}$ and 2090 ${\mathrm{cm}}^{-1}$, respectively. Then correct statement about metal carbonyls is :

(1) 'C-O' bond is strongest in the cation and weakest in the anion.

(2) 'C-O' bond is weakest in the cation and strongest in the anion.

(3) 'C-O' bond is longer in the cation than in the anion.

(4) 'M-C' pi bonding is higher in the cation.

The $\mathrm{\pi }$-acid ligand which uses its d-orbital during synergic bonding in its complex compound:

(1) ${\mathrm{NO}}^{+}$     

(2) ${\mathrm{PR}}_3$   

(3) ${\mathrm{C}}_6{\mathrm{H}}_6$   

(4) $\mathrm{CO}$

Correct sequence of CO bond order in given compounds is:

(P) $\mathrm{Fe}(\mathrm{CO}{)}_5$   (Q) CO    (R) ${\mathrm{H}}_3\mathrm{B}\stackrel{}{\leftarrow }\mathrm{CO}$     (S) $\left[\mathrm{Mn}\right(\mathrm{CO}{)}_5{]}^{+}$

1. P>R>S>Q                   

2. S>P>R>Q

3. Q>S>P>R                   

4. R>Q>S> P

In which of the following complex ion the value of magnetic moment (spin only) is $\sqrt{3}$

BM and outer d-orbitals is used in hybridization.

1. $\left[\mathrm{Mn}\right(\mathrm{CN}{)}_6{]}^{4-}$     

2. $\left[\mathrm{Fe}\right({\mathrm{NH}}_3{)}_6{]}^{3+}$     

3. $\left[\mathrm{Co}\right(\mathrm{CO}{)}_4]$         

4. $\left[\mathrm{Cu}\right({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$

The inner orbital complex that exhibits geometrical but not exhibit optical isomerism is -

(1) $\left[\mathrm{Cr}\right(\mathrm{en}{)}_3{]}^{3+}$                       

(2) $\left[{\mathrm{IrF}}_3\right({\mathrm{H}}_2\mathrm{O}{)}_2\left({\mathrm{NH}}_3\right)]$

(3) $\left[{\mathrm{NiCl}}_2\right(\mathrm{en}{)}_2]$                       

(4) $\left[\mathrm{Co}\right(\mathrm{CN}{)}_2(\mathrm{ox}{)}_2{]}^{3-}$