In the redox reaction $N_2H_4 + ClO_3^- \to NO + Cl^-$ (in basic medium),how many electrons are added in the reduction half-reaction based on the difference in oxidation states?

In the reaction between hydrogen sulphide and acidified permanganate solution,which of the following occurs?

Which of the following reactions is a redox reaction?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$S + HNO_3 \, (Dil.) \longrightarrow H_2SO_4 + NO \uparrow $

In an experiment,$50 \ mL$ of $0.1 \ M$ solution of a metal salt reacted with $25 \ mL$ of $0.1 \ M$ solution of sodium sulphite. The half-equation for the oxidation of sulphite ion is $SO_3^{2-}{(aq)} + H_2O_{(l)} \to SO_4^{2-}{(aq)} + 2H^{+}{(aq)} + 2e^-$. If the oxidation number of the metal in the salt was $3$,what would be the new oxidation number of the metal?

What is the number of moles of electrons gained by one mole of oxidizing agent in the following redox reaction?
$Zn_{(s)} + 2HCl_{(aq)} \longrightarrow ZnCl_2(aq) + H_2(g)$