The metal that gives hydrogen gas upon treatment with both acid as well as base is

Choose the correct statement and mark the correct option given below:
$(a)$ $AgF$ is soluble and colourless in aqueous medium.
$(b)$ For $LiF$,solubility and melting point are both lower as compared to $NaF$.
$(c)$ Solubility of $Rb_2SO_4$ is less as compared to $BaSO_4$.
$(d)$ If $AgI$ is added to water,the colour of water will turn yellow from colourless.

The main product obtained when a solution of sodium carbonate reacts with mercuric chloride is

Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.
$(a)$ Nitrates $(b)$ Carbonates $(c)$ Sulphates.

$A$ pink colored salt on dry heating becomes blue in colour. The salt may contain:

Identify the elements of alkali metals and alkaline earth metals respectively having the highest $1^{st}$ ionization enthalpy.