In a reaction the ferrous $(F{e^{ + 2 }})$ iron is oxidised to ferric $(F{e^{ + 3 }})$ ion. The equivalent weight of the ion in the above reaction is equal to

The number of unpaired electrons in ferrous ion is

For the ions $Zn ^{2+}, \,Ni ^{2+}$ and $Cr ^{3+}$ which among the following statements is correct ?

(Atomic number of $Zn =30,\,Ni =28$ and $Cr =24$ )

Which of the following ions will exhibit colour in aqueous solutions?

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products $\mathrm{A}$ and $\mathrm{B}$ along with the evolution of $\mathrm{CO}_2$. The sum of spin-only magnetic moment values of $A$ and $B$ is .......... $B.M.$ (Nearest integer)

(Given atomic number: $\mathrm{C}: 6, \mathrm{Na}: 11, \mathrm{O}: 8$, $\mathrm{Fe}: 26, \mathrm{Cr}: 24 \mathrm{~J}$

The correct order of decreasing second ionisation enthalpy of $Ti(22), V(23), Cr(24)$ and $Mn(25)$ is