For tooth decay, mouth pH below which value is considered harmful?
Answer and explanation
Correct answer: 5.5 / Five point five
Tooth enamel is mainly composed of calcium compounds and can be attacked when the mouth becomes sufficiently acidic. A mouth pH below about 5.5 is generally regarded as harmful because acid dissolution of enamel becomes significant. A pH of 7 is neutral, whereas 10 and 14 are alkaline values. Therefore, the accepted threshold in this school-level context is 5.5, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
5.5 / Five point five
Why is this the correct answer?
Tooth enamel is mainly composed of calcium compounds and can be attacked when the mouth becomes sufficiently acidic. A mouth pH below about 5.5 is generally regarded as harmful because acid dissolution of enamel becomes significant. A pH of 7 is neutral, whereas 10 and 14 are alkaline values. Therefore, the accepted threshold in this school-level context is 5.5, so option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
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