Which substance has the lowest open bracket cap h raised to the plus power close bracket concentration but is still considered an acid?

Acids have a pH below 7, and a higher pH means a lower hydrogen-ion (H⁺) concentration. Milk is mildly acidic, while gastric fluid is strongly acidic; blood and household lye are basic. Therefore, milk has the lowest H⁺ concentration among the substances that are still acids.

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