Question

Question 06.
Calcium phosphate is present in tooth enamel. Its nature is
(a) basic
(b) acidic
(c) neutral
(d) amphoteric

Answer 1

Calcium phosphate, ${\text{Ca}}_3({\text{PO}}_4{)}_2$, is formed when phosphoric acid, $\left({\text{H}}_3{\text{PO}}_4\right)$, a weak acid combines with a slightly stronger base, calcium hydroxide $\left({\text{Ca(OH)}}_2\right)$. Hence, calcium phosphate is basic in nature.
Also when pH of our mouth falls below 5.5, the mouth becomes acidic, the dissolution of enamel (calcium phosphate) begins which confirms ${\text{Ca}}_3{\text{(PO}}_4{)}_2$ is basic in nature.