The enamel present on teeth becomes much harder due to the conversion of $\left[3…

The enamel present on teeth becomes much harder due to the conversion of $\left[3 \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2, \mathrm{X}\right]$ into $\left[3 \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2, \mathrm{Y}\right]$. What are X and Y ?
  1. $\mathrm{X}=\mathrm{Ca}(\mathrm{OH})_2, \mathrm{Y}=\mathrm{CaF}_2$
  2. $\mathrm{X}=\mathrm{Ca}(\mathrm{OH})_2, \mathrm{Y}=\mathrm{CaCl}_2$
  3. $\mathrm{X}=\mathrm{Ca}(\mathrm{OH})_2, \mathrm{Y}=\mathrm{NaCl}$
  4. $\mathrm{X}=\mathrm{CaO}, \mathrm{Y}=\mathrm{CaCl}_2$

Solution

Calcium phosphate hydroxy apatite. $\begin{aligned} & 3 \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2 \cdot \mathrm{Ca}(\mathrm{OH})_2+2 \mathrm{~F}^{-} \rightarrow 3\left[\mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2 \cdot \mathrm{CaF}_2\right] \\ & \mathrm{X}=\mathrm{Ca}(\mathrm{OH})_2 \\ & \mathrm{Y}=\mathrm{CaF}_2 \end{aligned}$

Asked in: AP EAMCET 2024 (21 May Shift 2)

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