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

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?

What is the equivalent mass of $IO_4^-$ when it is converted into $I_2$ in an acidic medium?

After balancing the equation,$C_2O_4^{2-} + H^+ + MnO_4^- \longrightarrow CO_2 + Mn^{2+} + H_2O$,the coefficient of $CO_2$ is:

The number of electrons involved in the reduction of $Cr_2O_7^{2-}$ in acidic solution to $Cr^{3+}$ is

For the redox reaction $MnO_4^{-} + C_2O_4^{2-} + H^{+} \rightarrow Mn^{2+} + CO_2 + H_2O$,the correct coefficients of the reactants for the balanced reaction are respectively $MnO_4^{-}$,$C_2O_4^{2-}$ and $H^{+}$: