Which of the following compounds will exhibit coordination isomerism?

Geometrical isomerism can be shown by

Explain optical isomerism.

$[Fe(NO_{2})_{3} Cl_{3}]$ and $[Fe(ONO)_{3} Cl_{3}]$ show

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.

Calculate the magnetic moment of the $Fe^{3+}$ ion in the $[Fe(CN)_6]^{3-}$ complex.