Assign $A, B, C, D$ for the given type of reaction:
$Mn(NO_3)_2 + 2NaOH \longrightarrow Mn(OH)_2 \downarrow + 2NaNO_3$

When mercury $(II)$ chloride is treated with an excess of $SnCl_2$, the products obtained are:

Assign $A, B, C, D$ from the given type of reaction.
$CaSO_4 + Pb(NO_3)_2 \longrightarrow PbSO_4 \downarrow + Ca(NO_3)_2$

$50 \ cm^{3}$ of $0.04 \ M \ K_{2}Cr_{2}O_{7}$ in acidic medium oxidizes a sample of $H_{2}S$ gas to sulphur. The volume of $0.03 \ M \ KMnO_{4}$ required to oxidize the same amount of $H_{2}S$ gas to sulphur in acidic medium is: (in $cm^{3}$)

Which of the following reactions is $NOT$ an example of a redox reaction?

Suggest a scheme of classification of the following redox reactions:
$(a) N_{2(g)} + O_{2(g)} \rightarrow 2NO_{(g)}$
$(b) 2Pb(NO_3)_{2(s)} \rightarrow 2PbO_{(s)} + 4NO_{2(g)} + O_{2(g)}$
$(c) NaH_{(s)} + H_2O_{(l)} \rightarrow NaOH_{(aq)} + H_{2(g)}$
$(d) 2NO_{2(g)} + 2OH^{-}_{(aq)} \rightarrow NO_2^-(aq) + NO_3^-(aq) + H_2O_{(l)}$