All the elements of group $2$ react with water to form metal hydroxide and hydrogen,except the element

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Barium carbonate is insoluble in water and is highly stable.
Reason $R$: The thermal stability of the carbonates increases with increasing cationic size.
Choose the most appropriate answer from the options given below for $A$ and $R$.

Bleaching powder is obtained by passing chlorine on

Which of the following reactions represents the "slaking of lime"?

Which of the following sets represents the alkaline earth metals?

The alkaline earth metal with the lowest density is