When mercury $(II)$ chloride is treated with excess of stannous chloride,the products obtained are

$Na_2S_2O_3$ is

What volume of $O_{2(g)}$ measured at $1 \ atm$ and $273 \ K$ will be formed by the action of $100 \ mL$ of $0.5 \ N \ KMnO_4$ on hydrogen peroxide in an acidic solution? The skeleton equation for the reaction is: $KMnO_4 + H_2SO_4 + H_2O_2 \to K_2SO_4 + MnSO_4 + O_2 + H_2O$.

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

$A$ solution of $KMnO_{4}$ on reduction yields either a colourless solution,a brown precipitate,or a green solution depending on the $pH$ of the solution. What different stages of the reduction do these represent and how are they carried out?

$HNO_2$ acts as