State the reasons for the following:
$(a)$ Why is a solution of $Na_{2}CO_{3}$ alkaline?
$(b)$ Why are alkali metals prepared by the electrolysis of their fused chlorides?
$(c)$ Why is sodium found to be more useful than potassium in biological systems?

(N/A) When $Na_{2}CO_{3}$ is dissolved in water,it undergoes hydrolysis to form $NaHCO_{3}$ and $NaOH$. Since $NaOH$ is a strong base,the resulting solution becomes alkaline.
$Na_{2}CO_{3} + H_{2}O \longrightarrow NaHCO_{3} + NaOH$
$(b)$ Alkali metals are strong reducing agents and cannot be prepared by the chemical reduction of their oxides. They cannot be obtained by displacement reactions because they are highly electropositive. Electrolysis of aqueous solutions is also not feasible because the liberated metals react with water. Therefore,they are prepared by the electrolysis of their fused chlorides.
$(c)$ Sodium ions $(Na^+)$ are primarily found in blood plasma and interstitial fluids,playing a crucial role in nerve signal transmission,regulating water flow across cell membranes,and transporting sugars and amino acids into cells. While potassium ions $(K^+)$ are essential within cells,sodium's specific extracellular functions make it highly significant for physiological processes.