Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$2BaCrO_4 \downarrow + 4HCl \longrightarrow 2BaCl_2 + H_2Cr_2O_7 + H_2O$

$6 \times 10^{-3} \text{ mole}$ of $K_2Cr_2O_7$ reacts completely with $9 \times 10^{-3} \text{ mole}$ of $X^{n+}$ to give $XO_3^-$ and $Cr^{3+}$. The value of $n$ is:

Which of the following species is both basic and a reducing agent?

$50 \ mL$ 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?

Which of the following combinations does not evolve $Cl_2$ gas?

$x, y$ and $z$ are respectively:
$MnO_4^- + x e^- \xrightarrow{\text{Alkaline medium}} MnO_4^{2-}$
$MnO_4^- + y e^- \xrightarrow{\text{Acidic medium}} Mn^{2+}$
$MnO_4^- + z e^- \xrightarrow{\text{Neutral medium}} MnO_2$