What is the basicity of ${\mathrm{H}}_3{\mathrm{PO}}_4$?

The chemical formulae of some acids are given in the box. Pick out the monobasic and dibasic acids from them.

You are familiar with soda water, aren't you? How do you make it? The equation of this reaction is given below.

${\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2\to {\mathrm{H}}_2{\mathrm{CO}}_3$

Complete the equation for the dissolution of ${\mathrm{SO}}_2$ in water.

_____ $+$ _____ $\to {\mathrm{H}}_2{\mathrm{SO}}_3$ (Sulphurous acid)

From the oxides given below, find out the basic oxides.

Chemical names and formulae of some familiar alkalies are given in the table. Complete the table.

Complete the given equation of the ionisation of calcium hydroxide.

$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\to {\mathrm{Ca}}^{2+}+$ _____.