What is the oxidation state of osmium in $7B$ and $7C$,respectively?

The manganate and permanganate ions are tetrahedral,due to

The metal that does not give the borax bead test is

When $Cu^{2+}$ ion is treated with $KI$,a white precipitate,$X$ appears in solution. The solution is titrated with sodium thiosulphate,the compound $Y$ is formed. $X$ and $Y$ respectively are

The oxidation number of $Mn$ in the product of alkaline oxidative fusion of $MnO_2$ is

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