The salt of an alkali metal gives yellow colour in the flame test. Also, its aqueous solution gives an insoluble white precipitate with barium chloride in acid medium. The salt is
 

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason $\mathrm{R}$. Assertion $\mathrm{A}$ : $\mathrm{LiF}$ is sparingly soluble in water. Reason $\mathrm{R}$ : The ionic radius of ${\mathrm{Li}}^{+}$ ion is smallest among its group members, hence has least hydration enthalpy.

In the light of the above statements, choose the most appropriate answer from the options given below.

Match List-I with Match List-II

Choose the most appropriate answer from the options given below

The correct order of hydration enthalpies is

(A) ${\mathrm{K}}^{+}$
(B) ${\mathrm{Rb}}^{+}$
(C) ${\mathrm{Mg}}^{2+}$
(D) ${\mathrm{Cs}}^{+}$
(E) ${\mathrm{Ca}}^{2+}$

Choose the correct answer from the options given below:

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Lithium salts are hydrated.
Reason (R) : Lithium has higher polarising power than other alkali metal group members.

In the light of the above statements, choose the most appropriate answer from the options given below :

Choose the correct answer from the options given below:

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic.
Reasons R: The deep blue solution is due to the formation of amide.

In the light of the above statements, choose the correct answer from the options given below: