Question

Which of these substances is the most basic (alkaline)?

solution A, pOH = 1.5

solution B, pOH = 7.0

solution C, pOH = 13.5

Answer 1

Solution A is the most basic.

Reason: lower pOH means higher [OH−]. pH = 14 − pOH, so
- A: pH = 14 − 1.5 = 12.5 (basic)
- B: pH = 7.0 (neutral)
- C: pH = 14 − 13.5 = 0.5 (acidic)

Also [OH−] = 10^(−pOH), so A has the largest [OH−] (≈3.16×10^−2 M).