Complete the equations of the ionisation of phosphoric acid.

${\mathrm{H}}_3{\mathrm{PO}}_4\to {\mathrm{H}}^{+}+{\mathrm{H}}_2{{\mathrm{PO}}_4}^{–}$ (Dihydrogen phosphate ion)

${\mathrm{H}}_2{{\mathrm{PO}}_4}^{–}\to {\mathrm{H}}^{+}+$ _____ (Hydrogen phosphate ion)

_____ $\to {\mathrm{H}}^{+}+{{\mathrm{PO}}_4}^{3-}$ (phosphate ion)

Write the chemical name of the following salts.

$\mathrm{Mg}({\mathrm{H}}_2{\mathrm{PO}}_4{)}_2$

${\mathrm{MgHPO}}_4$

${\mathrm{Mg}}_3({\mathrm{PO}}_4{)}_2$

Solution of sodium carbonate, potassium chloride, and ammonium sulphate are taken in separate beakers. 

Recall the colour change of litmus paper in each solution and tabulate.

Solution of sodium carbonate, potassium chloride, and ammonium sulphate are taken in separate beakers. 

Name the acid and alkali that react to form each salt given above?

Solution of sodium carbonate, potassium chloride, and ammonium sulphate are taken in separate beakers. 

Can you explain the colour change of the litmus paper on the basis of the nature of the acid and alkali that react to form the salt?

(hint: Potassium chloride is a salt formed by the reaction between a strong acid and a strong alkali)