Among $C$,$S$,and $P$,the element$(s)$ that produce$(s)$ $SO_{2}$ on reaction with hot conc. $H_{2}SO_{4}$ is / are

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

Identify the type of the following chemical reaction:
$CuSO_4 + 2KI \longrightarrow CuI \downarrow + \frac{1}{2} I_2 + K_2SO_4$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$3AgNO_3 + Na_3PO_4 \longrightarrow Ag_3PO_4 \downarrow + 3NaNO_3$

In which of the following reactions is there no change in valency?

In chloro-alkali industries,during the Solvay ammonia process,a redox change occurs during: