Which has the highest `pH`?

Options

A. `CH_(3)COOK`
B. `Na_(2)CO_(3)`
C. `NH_(4)Cl`
D. `NaNO_(3)`

Answer

B

Explanation

`pH=log``(1)/([H^(+)])`
`pH` is inversely proportional to hydrogen ion concentration. As the concentration of `H^(+)` decreases, `pH` increases and vice versa
Ammonium chloride `(NH_(4)Cl)` is a salt of weak base and strong acid. So, its aqueous solution will be acidic as
`NH_(4)Cl+H_(2)O rarr underset(weak acid)(NH_(4)OH)+underset(strong base)(HCl)`
So, `pH` of `NH_(4)Cl` is less than `7`.
Sodium nitrate `(NaNO_(3))` is the salt of strong acid and strong base. So, its aqueous solution in neutral as
`NaNO_(3)+H_(2)O rarr underset(Strong base)(NaOH)+underset(Strong base)(HNO_(3))`
So, `pH` of `NaNO_(3)` is `7`.
Potassium acetate `(CH_(3)COOK)` is a salt of strong base and weak acid. Its aqueous solution will be basic and `pH` value will be `gt7~~8.8`
`CH_(3)COOK+H_(2)O rarr underset(Weak acid)(CH_(3)COOH+underset(Strong base)(KOH)`
Sodium carbonate `(Na_(2)CO_(3))` is a salt of strong base and weak acid. Its sodium is also basic and its `pH` value will be more than `10`.
`Na_(2)CO_(3)+H_(2)O rarr underset(Strong acid)(2NaOH)+underset(Weak acid)(H_(2)CO_(3))`