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Science · 2023 · 3 marks
CBSE 2023 · Region 1 · Set 2 · Q32
Write the chemical composition of tooth enamel. Under what conditions of pH it starts corroding ? Explain the reason of tooth decay and suggest one method to prevent it.
Marking-scheme solution
Calcium phosphate / Calcium hydroxyapatite
\(\displaystyle \left(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\right)\)
Tooth decay starts when the pH of the mouth is lower than 5.5.
Bacteria present in the mouth produces acid by degrading sugar and food particles.
Using Toothpaste / Cleaning the mouth after every meal.
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CBSE Class 10 Science past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.