Tooth enamel starts to dissolve and decay begins when the pH in the mouth falls below about

5.5Correct answerYour answer7Correct answerYour answer8.5Correct answerYour answer10Correct answerYour answer

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CorrectNot quiteAnswer A

Correct answer: A

Bacteria in the mouth break down sugar left on the teeth and produce acids.
Below about pH 5.5, the enamel (calcium phosphate) starts to dissolve. Toothpastes are basic to neutralise this acid.

Worth noting

A pH of 7 is neutral; enamel is safe there. The damage begins only in clearly acidic conditions.

Ten questions from Everyday Chemistry, at your own pace.

Ten questions from Everyday Chemistry, at your own pace.

Explanation