Give any two uses of washing soda.

Explain why is sodium less reactive than potassium?

Sodium carbonate reacts with $SO_2$ in aqueous medium to give

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

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $LiF$ is sparingly soluble in water.
Reason $R$: The ionic radius of $Li^{+}$ ion is smallest among its group members,hence it has the least hydration enthalpy.
In the light of the above statements,choose the most appropriate answer from the options given below.

Match the following metals with their oxidizing flame color.

Compound	Flame color
$1$. $Li$	$a$. Crimson red
$2$. $K$	$b$. Violet
$3$. $Cs$	$c$. Blue