Question

Assertion- Decay of teeth is due to the decrease in pH in the mouth. Reason-Acids released slowly destroy the enamel coating which protect teeth. (a) a (b) b (c) c (d) d​

Answer 1

Answer:

the answer is Tooth decay starts when the pH of the acid formed in the mouth falls below 5.5 because the acid becomes strong enough to attack the enamel of the teeth and corrode it.

(b) The pH of lake water becomes lower because of too much acid rain. The high acidity of lake water can kill the aquatic animals like fish since they can survive within a narrow range of pH change. Calcium carbonate is added to acidic lake water to neutralise the acid and this prevents the fish from being killed.

Answer 2

Answer: Option a

Explanation: Both assertion and reason are correct