Question

pH value of 0.001 M NaOH solution is _______.

Answer 1

Correct Answer: 11

To determine the pH value of a 0.001 M NaOH solution, we must first understand that NaOH is a strong base dissociating completely in water to produce OH^- ions. This dissociation can be represented by the equation:

NaOH → Na⁺ + OH^-

Thus, the concentration of OH^- ions in the solution is 0.001 M. The pOH of a solution is calculated using the formula:

pOH = -log[OH^-]

Substituting the given concentration:

pOH = -log(0.001) = 3

Given that pH + pOH = 14 for any aqueous solution at 25°C, we can find the pH as follows:

pH = 14 - pOH

pH = 14 - 3 = 11

The calculated pH value is 11, which confirms it falls within the expected range (11, 11) as specified.