| Acid strength | [H + ] | pH | pOH | [OH – ] |
| strong base | E-14 | 14 | 0 | E-0 |
| E-13 | 13 | 1 | E-1 | |
| base | E-12 | 12 | 2 | E-2 |
| E-11 | 11 | 3 | E-3 | |
| slightly base | E-10 | 10 | 4 | E-4 |
| E-9 | 9 | 5 | E-5 | |
| E-8 | 8 | 6 | E-6 | |
| NEUTRAL | E-7 | 7 | 7 | E-7 |
| E-6 | 6 | 8 | E-8 | |
| E-5 | 5 | 9 | E-9 | |
| slightly acid | E-4 | 4 | 10 | E-10 |
| E-3 | 3 | 11 | E-11 | |
| acid | E-2 | 2 | 12 | E-12 |
| E-1 | 1 | 13 | E-13 | |
| strong acid | E-0 | 0 | 14 | E-14 |