Where is potassium dichromate used?

$FeSO_4 \cdot 7H_2O$ (Green Vitriol) salt on thermal decomposition does not produce

Iodine is formed when potassium iodide reacts with a solution of

Which of the following is a product of the first step and is used as a reactant in the next step for the manufacture of $K_{2}Cr_{2}O_{7}$ from concentrated chromite ore?

$Orange-(A)$ (Inorganic compound) $+ H^{+} + H_2O_2 \to Blue-(B)$. The oxidation state of the central atom in compound $(B)$ is:

Among the following,the compound that is both paramagnetic and coloured is