Question

What is the pH of a 0.1 M NaOH solution?

• A. 12
• B. 13
• C. 14
• D. 11

Hint:

For strong bases like NaOH, the pH can be calculated using the formula: \(\text{pH} = 14 - \text{pOH}\).

Answer 1

The Correct Option is C

NaOH is a strong base and dissociates completely in water. The concentration of hydroxide ions (\(\text{OH}^-\)) is equal to the concentration of NaOH, which is 0.1 M. Step 1: Write the dissociation equation \[ \text{NaOH} \to \text{Na}^+ + \text{OH}^- \] The concentration of \(\text{OH}^-\) is 0.1 M. Step 2: Calculate the pOH The formula for pOH is: \[ \text{pOH} = -\log[\text{OH}^-] \] Substituting the concentration of \(\text{OH}^-\): \[ \text{pOH} = -\log(0.1) = -\log(10^{-1}) = 1 \] Step 3: Calculate the pH The relationship between pH and pOH is: \[ \text{pH} + \text{pOH} = 14 \] Thus: \[ \text{pH} = 14 - 1 = 13 \] Answer: The pH of the solution is 13, so the correct answer is option (2).