Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator. The number of moles of Mohr's salt required per mole of dichromate is

$C +$ Conc. $H_2SO_4 \xrightarrow{\Delta} X + Y + H_2O$. $X$ and $Y$ in the above reaction are:

The number of electrons required to balance the following equation $NO_3^- + 4H^+ + x e^- \to 2H_2O + NO$ is

In the following reaction,$I_2 + 5Cl_2 + 6H_2O \longrightarrow X + Y$,the products $X$ and $Y$ respectively are:

Assign $A, B, C, D$ from the given type of reaction.
$MnSO_4 + Sr(NO_3)_2 \longrightarrow SrSO_4 \downarrow + Mn(NO_3)_2$

Balance the following redox reactions by the ion-electron method:
$(a)$ $MnO_4^-(aq) + I^{-}(aq) \rightarrow MnO_2(s) + I_2(s)$ (in basic medium)
$(b)$ $MnO_4^-(aq) + SO_2(g) \rightarrow Mn^{2+}(aq) + HSO_4^-(aq)$ (in acidic solution)
$(c)$ $H_2O_2(aq) + Fe^{2+}(aq) \rightarrow Fe^{3+}(aq) + H_2O(l)$ (in acidic solution)
$(d)$ $Cr_2O_7^{2-} + SO_2(g) \rightarrow Cr^{3+}(aq) + SO_4^{2-}(aq)$ (in acidic solution)