Identify pair of neutral co-ordination entity amongst the following

(P) $\left[{\mathrm{CoCl}}_3{\left({\mathrm{NH}}_3\right)}_3\right]$ (Q) $\left[\mathrm{Ni}(\mathrm{CO}{)}_4\right]$

(R) $\left[{\mathrm{PtCl}}_2{\left({\mathrm{NH}}_3\right)}_2\right]$ (S) ${\mathrm{K}}_4\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]$

(T) $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]{\mathrm{Cl}}_3$

A neutral complex is a coordination complex that does not ionise and therefore does not produce charged species.

The correct pair of neutral co-ordination entity are,

$\left[{\mathrm{CoCl}}_3{\left({\mathrm{NH}}_3\right)}_3\right]$ and $\left[\mathrm{Ni}(\mathrm{CO}{)}_4\right]$

$\left[\mathrm{Ni}(\mathrm{CO}{)}_4\right]$ and $\left[{\mathrm{PtCl}}_2{\left({\mathrm{NH}}_3\right)}_2\right]$

Thus, the correct answer is b, c.