Question

Which of the following salt of Calcium is used in the preparation of super phosphate of lime ?

• A. Ca₃(PO₃)₂ (Calcium phosphite)
• B. Ca₃(PO₄)₂ (Calcium phosphate)
• C. Ca(HPO₄)₂ (Calcium mono-hydrogen phosphate.)
• D. CaSO4 (Calcium sulphate)

Answer 1

The correct option is B

Ca₃(PO₄)₂ (Calcium phosphate)

Super phosphate of lime (Ca₃(H₂PO₄)₂ )

It is a widely used as phosphatic fertilizer

Preparation of Super phosphate of lime:

Which is prepared by treating Calcium phosphate with concentrated sulphuric acid.

$$\begin{gathered} {\mathrm{Ca}}_3{\left({\mathrm{PO}}_4\right)}_2\left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to 2{\mathrm{CaSO}}_4\left(\mathrm{aq}\right)+\mathrm{Ca}{\left({\mathrm{H}}_2{\mathrm{PO}}_4\right)}_2\left(\mathrm{aq}\right) \\ \mathrm{Calcium}\mathrm{Sulphuric}\mathrm{acid}\mathrm{Calcium}\mathrm{super}\mathrm{phosphate} \\ \mathrm{phosphate}\mathrm{sulphate}\mathrm{of}\mathrm{lime} \end{gathered}$$

Conclusion: Therefore Ca₃(PO₄)₂ (Calcium phosphate) is used in the preparation of Super phosphate of lime