Number of moles of $SnCl_2$ required for the reduction of $1$ mole of $K_2Cr_2O_7$ into $Cr^{3+}$ (in acidic medium) is:

If the molecular weights of $Na_2S_2O_3$ and $I_2$ are $M_1$ and $M_2$ respectively,then what will be the equivalent weights of $Na_2S_2O_3$ and $I_2$ in the following reaction?
$2S_2O_3^{2-} + I_2 \longrightarrow S_4O_6^{2-} + 2I^-$

The oxidation state of chromium in the final product formed in the reaction between $KI$ and acidified $K_{2}Cr_{2}O_{7}$ solution is:

In which reaction is there a change in the oxidation state?

The number of electrons required to reduce chromium completely in $Cr_2O_7^{2-}$ to $Cr^{3+}$ in acidic medium is:

The number of moles of ferrous oxalate oxidized by one mole of $KMnO_4$ in acidic medium is