$KMnO_4$ oxidises $C_2H_2O_4$ to form $CO_2$. In which of the following,the reaction will be faster?

$X + H_2SO_4 \to Y$ (colorless gas) and $Y + K_2Cr_2O_7 + H_2SO_4 \to$ green solution. Then $X$ and $Y$ are respectively ........

In acidic medium, one mole each of $MnO_4^-$ and $Cr_2O_7^{2-}$ is reduced by $x$ and $y$ moles of ferrous ions $(Fe^{2+})$ respectively. The sum of $x$ and $y$ is:

Whenever a reaction between an oxidising agent and a reducing agent is carried out,a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations.

Which of the following reduction products of $NO_3^-$ involves the maximum number of moles of electrons taken up per mole of $NO_3^-$?

Equivalent weights of $KMnO_4$ and $K_2Cr_2O_7$ in acidic medium are respectively. (Molecular weight of $KMnO_4 = M_A$ and Molecular weight of $K_2Cr_2O_7 = M_B$).