Question

Rank these solutions from the most alkaline (1) to the least alkaline (5).

pOH = 0.5
pH = 3.5
[OH–] = 5.62 × 10–5 M
[H3O+] = 3.16 × 10–7 M
pH = 0.5

Answer 1

More alkaline = higher pH. Converting each to pH:

- pOH = 0.5 → pH = 14 − 0.5 = 13.50
- [OH−] = 5.62×10⁻⁵ M → pOH = −log(5.62×10⁻⁵) ≈ 4.25 → pH ≈ 14 − 4.25 = 9.75
- [H3O+] = 3.16×10⁻⁷ M → pH = −log(3.16×10⁻⁷) ≈ 6.50
- pH = 3.5 → pH = 3.50
- pH = 0.5 → pH = 0.50

Ranked from most alkaline (1) to least alkaline (5):
1) pOH = 0.5
2) [OH−] = 5.62×10⁻⁵ M
3) [H3O+] = 3.16×10⁻⁷ M
4) pH = 3.5
5) pH = 0.5