What is the PH of a 1 Millimolar NaOH Solution

Question

What is the pH of a 1 millimolar NaOH solution?
A) pH 3
B) pH 8
C) pH 9
D) pH 10
E) pH 11

Accepted Answer

A 1 millimolar (1 mM or 0.001 M) NaOH solution is a basic solution. The concentration of OH- ions in the solution is 0.001 M. The pOH of the solution can be calculated using the formula pOH = -log[OH-], which gives pOH = 3. Since pH + pOH = 14 for aqueous solutions at 25°C, the pH of the solution is 14 - 3 = 11.