Question

Which has highest $pH$:-

• A. $C{H}_{3}COOK$
• B. $N{a}_{2}C{O}_3$
• C. $N{H}_{4}Cl$
• D. $NaN{O}_3$

Answer 1

Answer: (B)

Hint: From the composition of salt we can find out whether it is weak acid or base.
Explanation:
$N{H}_{4}Cl$ is acidic since it is salt of strong acid $(HCl)$ and weak base $\left(N{H}_{4}OH\right)$.
$\therefore p{H}_{N{H}_{4}C1}<7$
$NaN{O}_3$ is neutral since it salt of strong acid $\left(HN{O}_3\right)$ and strong base $(NaOH)$.
$\therefore p{H}_{NaN{O}_3}=7$
$C{H}_{3}COOK$ is weakly basic since it the salt of a weak acid $\left(C{H}_{3}COOH\right)$ and strong base $(KOH)$
$\therefore p{H}_{C{H}_{3}COOK}>7$
$N{a}_{2}C{O}_3$ is the stronger base because it is the salt of weak acid $H_{2}C{O}_3$ and strong acid $NaOH$
$\therefore p{H}_{N{a}_{2}C{O}_3}>p{H}_{C{H}_{3}COOK}>7$