Tooth enamel is made of:
ACalcium phosphate
BCalcium carbonate
CCalcium sulphate
DSodium chloride
Answer & Solution
Correct answer: A. Calcium phosphate
1. Tooth enamel is largely hydroxyapatite: Ca₅(PO₄)₃(OH) — a calcium phosphate.
2. Hardest substance in the human body.
3. Acids from bacteria fermenting sugar dissolve enamel → cavities. Toothpaste (basic) helps neutralise this.
_Source: NCERT Class 10 Science Ch 2 §2.3 Tooth Decay_
Related questions
pH of the stomach (gastric juice) is approximately:An acid that is also a strong dehydrating agent and is used in car batteries is:Plaster of Paris (POP) has the formula:The salt formed from NaOH + HCl is:When a carbonate reacts with an acid, the gas evolved is:When an acid reacts with a metal, the gas usually evolved is:Washing soda is sodium carbonate decahydrate, formula:Baking soda (sodium hydrogen carbonate) has the formula: