Why does mouth pH decrease during tooth decay?
Answer and explanation
Correct answer: Bacteria form acids from sugar
The governing concept is bacterial fermentation and pH. Food sugars left on teeth are metabolised by oral bacteria, which produce organic acids. The increased hydrogen-ion concentration lowers mouth pH, making the tooth enamel vulnerable to demineralisation and decay. Thus option A is correct. Toothpaste is generally basic, saliva does not always form a base, and teeth do not produce hydrogen gas.
Frequently asked questions
What is the correct answer to this question?
Bacteria form acids from sugar
Why is this the correct answer?
The governing concept is bacterial fermentation and pH. Food sugars left on teeth are metabolised by oral bacteria, which produce organic acids. The increased hydrogen-ion concentration lowers mouth pH, making the tooth enamel vulnerable to demineralisation and decay. Thus option A is correct. Toothpaste is generally basic, saliva does not always form a base, and teeth do not produce hydrogen gas.
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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