Question

Deficiency of `(F^(-))` in drinking water causes tooth decay. Its International Standard limit makes the enamal on tooth much harder by comverting hydroxyapatite into much harder
A. `Ca_(3)(PO_4)_(2).CaF_(2)`
B. `Ca_(3)(PO_4)_(2).3CaF_(2)`
C. `3Ca_(3)(PO_4)_(2).CaF_(2)`
D. `3Ca_(3)(PO_4)_(2).3CaF_(2)`

Answer 1

Correct Answer - C
Hydroxyapatite is `3Ca(PO_4)_(2).Ca(OH)_(2)`. Fluoride converts it into fluorapatite `3Ca_(3)(PO_4)_(2).CaF_(2)`.