Question

The pH of $0.1\text{M}$ $\mathrm{NaOH}$ is

• A. $10$
• B. $11$
• C. $12$
• D. $13$

Answer 1

The correct option is D

$13$

The explanation for the correct option

(D) $13$

Step1. Formula of pOH

$\text{pOH}=-\log \left[{\mathrm{OH}}^{-}\right]$

Here,$\left[{\mathrm{OH}}^{-}\right]$ is the concentration of hydroxyl ion.

Step2.Calculation of pOH

• Let's assume the solution is $0.1\text{M}$.
• $\mathrm{NaOH}$ is a strong base, so this will produce $0.1{\text{mol L}}^{-1}$ of $\text{OH}$ ions in solution.
• $$\begin{gathered} \text{pOH}=-\log \left[0.1\right] \\ =1 \end{gathered}$$

Step3. Relationship between pH and pOH

$\text{pH+pOH}=14$

Step4.Calculation of pH

$$\begin{gathered} \text{pH+1}=14 \\ \text{pH}=13 \end{gathered}$$

Hence, the value of pH is $13$.

The explanation for the incorrect option

The pH of $0.1\text{M}$ $\mathrm{NaOH}$ is $13$. Hence, options (A), (B), and (C) are incorrect.

So, option (D) is the correct option. The pH of $0.1\text{M}$ $\mathrm{NaOH}$ is $13$.