How many moles of $K_2Cr_2O_7$ will be reduced by $1$ mole of $Sn^{2+}$ ions?

In the balanced redox reaction $MnO_4^- + xFe^{2+} + yH^+ \rightarrow Mn^{2+} + 5Fe^{3+} + 4H_2O$,what are the values of $x$ and $y$?

In the reaction $2[Fe(CN)_6]^{3-} + H_2O_2 + 2OH^{-} \rightarrow 2[Fe(CN)_6]^{4-} + 2H_2O + O_2$,what is the equivalent weight of the reductant? $(Fe = 56, C = 12, N = 14, O = 16, H = 1)$

What is the number of electrons gained by $Cl$ atom when $n$ mole of $ClO_4^-$ is transformed into $n$ mole of $ClO_2^-$ ion?

When thiosulphate ion is oxidised by iodine,which one of the following ions is produced?

In the equation,$BiO_3^{-} + 6H^{+} + xe^{-} \rightarrow Bi^{3+} + 3H_2O$. What is the value of $x$?