Identify the substance acting as an oxidant in the following reaction:
$BaCl_2 + Na_2SO_4 \to BaSO_4 + 2NaCl$

$50 \ mL$ of $0.1 \ M$ solution of a salt reacted with $25 \ mL$ of $0.1 \ M$ solution of sodium sulphite. The half-reaction for the oxidation of sulphite ion is:
$SO_{3}^{2-} (aq) + H_{2}O (l) \to SO_{4}^{2-} (aq) + 2H^{+} (aq) + 2e^{-}$
If the oxidation number of the metal in the salt was $+3$,what would be the new oxidation number of the metal?

Iodine is released when potassium iodide reacts with

Match the following columns:-

Column-$I$ [Type of reaction]	Column-$II$ [Example]
$I$. Intermolecular redox reaction	$A$. $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$
$II$. Intramolecular redox reaction	$B$. $NH_4NO_2 \rightarrow N_2 + 2H_2O$
$III$. Disproportionation reaction	$C$. $2H_2O_2 \rightarrow 2H_2O + O_2$
$IV$. Comproportionation reaction	$D$. $KClO_3 \rightarrow KCl + \frac{3}{2}O_2$

Assign $A, B, C, D$ from the given type of reaction: $2NaNO_3 + H_2SO_4(conc.) \xrightarrow{Hot} Na_2SO_4 + 2NO_2 + \frac{1}{2}O_2 + H_2O$. (Note: The reaction is a thermal decomposition redox reaction).

Which of the following reactions is not a redox reaction?