pH scale.
A common one is this:
pH 0 - 2 Strongly acidic
pH 3 - 5 Weakly acidic
pH 6 - 8 Neutral
pH 9 - 11 Weakly basic
pH 12 - 14 Strongly basic
A common one is this:
pH 0 - 2 Strongly acidic
pH 3 - 5 Weakly acidic
pH 6 - 8 Neutral
pH 9 - 11 Weakly basic
pH 12 - 14 Strongly basic