Which of the following is a highly corrosive salt?

Match Column $A$ with Column $B$:

Column $A$	Column $B$
$(1) \ NiCl_2 \cdot 6H_2O$	$(a) \ \text{Pink}$
$(2) \ Co(NO_3)_2 \cdot 6H_2O$	$(b) \ \text{Colorless}$
$(3) \ FeCl_3$	$(c) \ \text{Blue}$
$(4) \ CuSO_4 \cdot 5H_2O$	$(d) \ \text{Green}$
	$(e) \ \text{Yellow}$

The false statement about iron $(III)$ hydroxide is that

When a chromite ore $(A)$ is fused with sodium carbonate in free excess of air and the product is dissolved in water,a yellow solution of compound $(B)$ is obtained. After treatment of this yellow solution with sulphuric acid,compound $(C)$ can be crystallised from the solution. When compound $(C)$ is treated with $KCl$,orange crystals of compound $(D)$ crystallise out. Identify $A$ to $D$ and also explain the reactions.

The colorless species 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: $C: 6, Na: 11, O: 8, Fe: 26, Cr: 24$)