Identify the statement which is not correct regarding $CuSO_{4}$.

In making gun-barrel,the steel used is

On heating a mixture of common salt and $K_{2}Cr_{2}O_{7}$ with concentrated $H_{2}SO_{4}$, a gas is evolved. The formula of the gas evolved and the oxidation state of the central metal atom in the gas, respectively, are:

The formula of corrosive sublimate is

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products $A$ and $B$ along with the evolution of $CO_2$. The sum of spin-only magnetic moment values of $A$ and $B$ is .......... $B.M.$ (Nearest integer)
(Given atomic number: $C: 6, Na: 11, O: 8, Fe: 26, Cr: 24$)

Acidified chromic acid $+ H_2O_2 \xrightarrow{\text{Org. solvent}} X + Y$ (blue colour). $X$ and $Y$ are: