# The conversion of hydroxyapatite occurs due to presence of

Question:

The conversion of hydroxyapatite occurs due to presence of $\mathrm{F}^{-}$ions in water. The correct formula of hydroxyapatite is:

1. $\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{Ca}(\mathrm{OH})_{2}\right]$

2. $\left[3 \mathrm{Ca}(\mathrm{OH})_{2} \cdot \mathrm{CaF}_{2}\right]$

3. $\left[\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{CaF}_{2}\right]$

4. $\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{CaF}_{2}\right]$

Correct Option: 1,

Solution:

The $\mathrm{F}^{\Theta}$ ions make the enamel on teeth much harder by converting hydroxyapatite, $\left[3\left(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\right] \cdot \mathrm{Ca}(\mathrm{OH})_{2}\right]$,

the enamel on the surface of the teeth into much harder fluroappatite. $\left[3 \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2} \cdot \mathrm{CaF}_{2}\right]$