Identify the element having general electronic configuration $ns^1$ from the following.

What is obtained by the electrolysis of carnallite?

On heating,$NaNO_3$ gives:

Compound $A$ is prepared by the electrolysis of an aqueous solution of $B$ using a Castner-Kellner cell with mercury as the cathode and carbon as the anode. $A$ and $B$ respectively are:

Which one of the following elements reduces $NaOH$ to $Na$?

Alkali metals have negative reduction potential and hence they behave as