Nelson cell is used for the preparation of

The oxide of $Cs$ is:

Which of the following compounds transforms baking soda into baking powder?

(Milky Cloud) $C \xleftarrow{CO_2} A + Na_2CO_3 \rightarrow B + C$
The chemical formulae of $A$ and $B$ are

In the synthesis of sodium carbonate,the recovery of ammonia is done by treating $NH_4Cl$ with $Ca(OH)_2$. The by-product obtained in this process is

Identify the correct statements from the following.
$A$: Alkali metals are strong reducing agents.
$B$: $KO_2$ is a diamagnetic oxide.
$C$: Hydration enthalpy of $Li^{+}$ is the highest among alkali metal ions.