Question

Which of the following basic solution will have the highest pH?

• A. Lemon juice
• B. $\mathrm{HCl}$
• C. Vinegar
• D. $\mathrm{NaOH}$

Answer 1

The correct option is D

$\mathrm{NaOH}$

Explanation for correct option:

Basic solution:

• A basic solution is an aqueous solution that contains more hydroxyl ions ${\mathrm{OH}}^{-}$than hydrogen ${\mathrm{H}}^{+}$ ions.
• It is an aqueous solution with a pH greater than $7$ at ${25}^{\mathrm{o}}\mathrm{C}$.
• Basic solutions turn red litmus paper blue.

Sodium hydroxide $\left(\mathrm{NaOH}\right)$ is a strong base as it dissociates completely into Hydroxyl ions ${\mathrm{OH}}^{-}$.

The dissociation of Sodium hydroxide can be represented as:

$\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Sodium}\mathrm{ion}}{{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydroxide}\mathrm{ion}}{{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$

The pH of sodium hydroxide solution is $13$ at ${25}^{\mathrm{o}}\mathrm{C}$.

Explanation for incorrect options:

Vinegar, $\mathrm{HCl}$ and lemon juice are acidic solutions with a pH below $7$ at ${25}^{\mathrm{o}}\mathrm{C}$.

Thus options. A,B and C are incorrect.

Hence, the correct option is (D).