$(a)$ Study the following chemical equation:
$CaSO_4 \cdot 2H_2O \xrightarrow{373K} CaSO_4 \cdot \frac{1}{2}H_2O + \frac{3}{2}H_2O$
Name the reactant and the product. State one use of the product.

In a basic aqueous solution,how does the basicity of the solution change as the concentration of $[OH^{-}]$ ions decreases?

Write true or false for the following statement:
Higher is the hydronium ion concentration,higher is the $pH$ value.

Which ions are responsible for the chemical properties of bases in their aqueous solution?

According to the Arrhenius theory,which ion is produced when a base ionizes in water?

Equal lengths of magnesium ribbon are taken in two test tubes $A$ and $B$. $H_{2}SO_{4}$ is added to test tube $A$ and $H_{2}CO_{3}$ in test tube $B$ in equal amounts.
$(a)$ Identify the test tube showing vigorous reaction.
$(b)$ Give reason to support your answer.
$(c)$ Name the gas liberated in both the test tubes. How will you prove its liberation?