Which of the following mixtures forms chromic acid?

The green colour produced in the borax bead test of a chromium$(III)$ salt is due to formation of . . . . . . :

What is the starting material for the preparation of $KMnO_4$?

The total number of $Mn=O$ bonds in $Mn_2O_7$ is

Describe the preparation of potassium permanganate. State its physical properties,structure,and uses. Discuss its chemical properties and provide chemical reactions demonstrating the oxidizing character of $KMnO_{4}$.

When acidified $K_2Cr_2O_7$ reacts with $H_2O_2$,a blue-coloured solution is obtained. This blue colour is due to the formation of: