pH value | Classification |
Very strongly acidic | <4.5 |
Strongly acidic | 4.6 to 5.5 |
Slightly acidic | 5.6 to 6.5 |
Neutral | 6.6 to 7.3 |
Slightly alkaline | 7.4 to 8.4 |
Strongly alkaline | 8.5 to 9.0 |