What is the equivalent weight of $K_2Cr_2O_7$ during the iodometric standardization of $Na_2S_2O_3$?

In a weak alkaline medium,iodide is changed into which of the following compounds by $KMnO_4$?

On balancing the given redox reaction,$aCr_2O_7^{2-} + bSO_3^{2-}{(aq)} + cH^{+}{(aq)}$ $\rightarrow 2aCr^{3+}{(aq)} + bSO_4^{2-}{(aq)} + \frac{c}{2}H_2O_{(l)}$,the coefficients $a$,$b$,and $c$ are found to be,respectively-

The number of electrons involved in the reduction of permanganate to manganese dioxide in acidic medium is $.......$.

In an acidic medium,the dichromate ion oxidizes the ferrous ion to the ferric ion. If the molar mass of potassium dichromate is $294 \, g/mol$,what is its equivalent mass?

What will happen when copper sulphate solution is stored in aluminium vessels?