The total possible coordination isomers for the following compounds respectively are :
$[Co(en)_3] [Cr(C_2O_4)_3]$
$[Cu(NH_3)_4] [CuCl_4]$
$[Ni(en)_3] [Co(NO_2)_6]$

Identify the ionization isomer of $[Cr(H_2O)_4 Cl(NO_2)] Cl$ from the following.

In an experiment,$m$ grams of a compound $X$ (gas/liquid/solid) taken in a container is loaded in a balance as shown in figure $I$ below. In the presence of a magnetic field,the pan with $X$ is either deflected upwards (figure $II$),or deflected downwards (figure $III$),depending on the compound $X$. Identify the correct statement$(s)$:
$(A)$ If $X$ is $H_2O_{(l)}$,deflection of the pan is upwards.
$(B)$ If $X$ is $K_4[Fe(CN)_6]_{(s)}$,deflection of the pan is upwards.
$(C)$ If $X$ is $O_{2(g)}$,deflection of the pan is downwards.
$(D)$ If $X$ is $C_6H_{6(l)}$,deflection of the pan is downwards.

The calculated spin-only magnetic moments $(BM)$ of the species $[Fe(CN)_6]^{4-}$ and $[Fe(H_2O)_6]^{2+}$,respectively,are:

The calculated magnetic moment value for the $Fe^{2+}$ ion in $BM$ is:

The spin-only magnetic moment of $Ni^{2+}$ in an aqueous solution in Bohr magneton $(\mu_B)$ is .......