Question

Which has highest $pH$:-

• A. $CH_3COOK$
• B. $Na_2CO_3$
• C. $NH_4Cl$
• D. $NaNO_3$

Answer 1

Answer: (B)

Hint: From the composition of salt we can find out whether it is weak acid or base.
Explanation:
$NH _{4} Cl$ is acidic since it is salt of strong acid $( HCl )$ and weak base $\left( NH _{4} OH \right)$.
$\therefore pH _{ NH _{4} C 1}< 7$
$NaNO _{3}$ is neutral since it salt of strong acid $\left( HNO _{3}\right)$ and strong base $( NaOH )$.
$\therefore pH _{ NaNO _{3}}=7$
$CH _{3} COOK$ is weakly basic since it the salt of a weak acid $\left( CH _{3} COOH \right)$ and strong base $( KOH )$
$\therefore pH _{ CH _{3} COOK } >7$
$Na _{2} CO _{3}$ is the stronger base because it is the salt of weak acid $H _{2} CO _{3}$ and strong acid $NaOH$
$\therefore pH _{ Na _{2} CO _{3}} > pH _{ CH _{3} COOK } >7$