Answer:
pH = 4
Step-by-step explanation:
Given data
[OH⁻] = 4.0 × 10⁻¹¹ M
Step 1: Calculate the pOH
We will use the following expression.
pOH = -log [OH⁻]
pOH = -log 4.0 × 10⁻¹¹
pOH = 10
Step 2: Calculate the pH
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH
pH = 14 - 10
pH = 4
The pH scale is used to define the acidity or alkalinity of a solution. in this case, since pH < 4, the solution is acid.