To find the pH of a solution from its pOH, we can use the relationship between pH and pOH:

pH + pOH = 14

We are given pOH = 8.7, so we can plug this value into the equation and solve for pH:

pH + 8.7 = 14

pH = 14 - 8.7

pH = 5.3

Therefore, the pH of the solution is 5.3.