Which of the following imparts green colour to the glass?

Potassium dichromate when heated with concentrated sulphuric acid and a soluble chloride,gives brown-red vapours of:

When a manganese $(Mn^{II})$ salt is fused with a mixture of $KNO_3$ and solid $NaOH$,what will be the oxidation state of $Mn$ after it changes from $+2$?

Identify $(A)$,$(B)$ and $(C)$ in the given reaction sequence:

Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing $pH$ on a solution of potassium dichromate?

The highest stable $Mn$ fluoride is $MnF_4$,whereas the highest $Mn$ oxide is $Mn_2O_7$. This is due to: