Which diagram correctly represents the change in the color of an aqueous solution of chromate ions?

Consider the following chemical reactions involved in the extraction of chromium from chromite ore:
$(a)$ $4FeCr_2O_4 + X_1 + 7O_2 \to 8Na_2CrO_4 + 2Fe_2O_3 + 8CO_2$
$(b)$ $2Na_2CrO_4 + X_2 \to Na_2Cr_2O_7 + 2Na^+ + H_2O$
Identify the species $X_1$ and $X_2$ in the reactions.

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

$X$ is an oxoanion of the lightest element of group $7$ in the periodic table. The metal is in $+6$ oxidation state in $X$. The color of the potassium salt of $X$ is

The conversion of pig iron to steel frequently requires the addition of
$(I)$ oxygen or iron oxide
$(II)$ transition elements
$(III)$ inner transition elements
$(IV)$ silica

Give the preparation of potassium dichromate and state its uses.
Give the structures of chromate and dichromate ions. How can chromates and dichromates be interconverted?
Give the chemical reactions showing the oxidizing nature of potassium dichromate.