Question

The pH of 0.01 M NaOH (aq) solution will be

• A. 7.01
• B. 2
• C. 12
• D. 9

Answer 1

The Correct Option is C

To determine the pH of a 0.01 M NaOH (aq) solution, we first need to understand the relationship between the pH and the concentration of a strong base like NaOH.

1. NaOH is a strong base and dissociates completely in water. The dissociation can be represented as: \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- .
2. The concentration of hydroxide ions [\text{OH}^-] is equal to the concentration of the NaOH solution. Therefore, in a 0.01 M NaOH solution, [\text{OH}^-] = 0.01 \, \text{M}.
3. The relationship between pH and pOH is given by the equation: \text{pH} + \text{pOH} = 14.
4. First, calculate the pOH of the solution: \text{pOH} = - \log_{10} [\text{OH}^-] = - \log_{10}(0.01).
5. Since 0.01 = 10^{-2}, \text{pOH} = 2.
6. Using the relation \text{pH} + \text{pOH} = 14, we find: \text{pH} = 14 - \text{pOH} = 14 - 2 = 12.

Thus, the pH of a 0.01 M NaOH solution is 12. This means that the solution is basic, as expected for a sodium hydroxide solution.

This confirms that the correct answer is 12, which matches the given correct option.