Give the correct order of electrical conductivity of aqueous solution of the following complexes:
$A$. $[Pt(NH_3)_6]Cl_4$
$B$. $[Cr(NH_3)_6]Cl_3$
$C$. $[Co(NH_3)_4Cl_2]Cl$
$D$. $K_2[PtCl_6]$

Which of the following properties are exhibited by the $CN^-$ ion towards metal compounds?
$(a)$ Reducing
$(b)$ Oxidizing
$(c)$ Complexing

The compound $ZnFe_2O_4$ is:

Given below are two statements:
Statement $I$ : $N(CH_3)_3$ and $P(CH_3)_3$ can act as ligands to form transition metal complexes.
Statement $II$: As $N$ and $P$ are from same group,the nature of bonding of $N(CH_3)_3$ and $P(CH_3)_3$ is always same with transition metals.
In the light of the above statements,choose the most appropriate answer from the options given below:

Solubility of iodine in water is greatly increased by the addition of iodide ions because of the formation of ......

In which one of the following pairs of ions is there an ion that forms a coordination compound with both aqueous sodium hydroxide and ammonia,and another ion that forms a coordination compound only with aqueous sodium hydroxide?