The colour of the bead in the borax bead test is mainly due to the formation of:

When $MnO_2$ is fused with $KOH$,a coloured compound is formed. The product and its colour are:

Each of the following ions contains vanadium in the $+V$ oxidation state except:

Chromite ore $\xrightarrow{Na_2CO_3 + O_2} A$ $\xrightarrow[NaOH]{H_2SO_4} B$. Which of the following is correct?

Paris green is

Fill in the blanks:
$(1)$ ......... acid is added to perform titrations with $KMnO_4$ and $K_2Cr_2O_7$.
$(2)$ Crystals of potassium dichromate are of ......... color,while crystals of potassium chromate are of ......... color.
$(3)$ The color of $MnO_4^{2-}$ is ......... and the color of $MnO_4^-$ is ......... .