Question

Choose the correct statement(s) for an aqueous solution of $N{a}_{2}C{O}_3$.

• A. The solution will be basic in nature
• B. The solution will be acidic in nature.
• C. Cationic $\left(N{a}^{+}\right)$ hydrolysis occurs.
• D. Anionic $\left(C{O}_3^{2-}\right)$ hydrolysis occurs

Answer 1

Answer: (A), (D)

Anionic $\left(C{O}_3^{2-}\right)$ hydrolysis occurs

$N{a}_{2}C{O}_3$ is a salt of strong base and weak acid.
On complete dissociation $N{a}_{2}C{O}_3\left(aq\right)\to C{O}_3^{2-}\left(aq\right)+2N{a}^{+}\left(aq\right)$
On hydrolysis $C{O}_3^{2-}\left(aq\right)+2H_{2}O\left(l\right)\rightleftharpoons H_{2}C{O}_3\left(aq\right)+2O{H}^{-}\left(aq\right))$

Note:- Only the anion will undergo hydrolysis and the solution will be alkaline in nature due to $O{H}^{-}$ formation.
So here, the anion $C{O}_3^{2-}$ is responsible for the alkaline nature of the solution.
$\Rightarrow pH>7$
Formula:
$pH=7+\frac{1}{2}(p{K}_a+logC)$