What is the formula of the product formed when `F^(-)` reacts with enamel on teeth ?

Options

A. `CaSO_(4), CaF_(2)`
B. `3Ca_(3)(PO_(4))_(2), PF_(5)`
C. `Ca_(2)SO_(4), CaF_(2)`
D. `3[Ca_(3)(PO_(4))_(2), CaF_(2)]`

Answer

D

Explanation

Enamel of teeth is `Ca_(10) (PO_(4))_(6)(OH)_(2)`, when it reacts with `F^(-)` ions, following reaction will take place.
`Ca_(10)(PO_(4))_(6)(OH)_(2)+2F^(-) rarr Ca_(10)(PO_(4))_(6)F_(2)+2OH^(-)`
`Ca_(10)(PO_(4))_(6)F_(2)` can be rewritten as :
`3[Ca_(3)(PO_(4))_(2)]CaF_(2)` or `3[Ca_(3)(PO_(4))_(2).CaF_(2)]`
Hence, option (d) is the correct answer.