CHEMISTRY

JAMB 2008 - Question 18

Chemistry 2008 JAMB Past Questions - Question 18: What is the pH of a 0.001 mol dm-³ solution of sodium hydroxide?

Choose the correct answers from the options given.
What is the pH of a 0.001 mol dm-³ solution of sodium hydroxide?
A:
B:
C:
D:
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Correct Answer

D

Explanation

The pH of a 0.001 mol dm-³ solution of sodium hydroxide is approximately 11.00.

Here's how we can calculate it:

1. **Sodium hydroxide (NaOH) is a strong base, meaning it completely dissociates in water to form Na+ and OH- ions.** This means that the concentration of OH- ions in the solution is equal to the concentration of NaOH, which is 0.001 mol dm-³.

2. **We can use the pOH formula to calculate the pOH of the solution:**

  pOH = -log[OH-]

  pOH = -log(0.001) = 3

3. **We can use the relationship between pH and pOH to calculate the pH of the solution:**

  pH + pOH = 14

  pH = 14 - pOH = 14 - 3 = 11

Therefore, the pH of the solution is approximately 11.00.