Question

Give four examples for preparation of acids by synthesis.

Answer 1

In the synthesis method, the direct combination of non-metals with hydrogen leads to formation of acidic gases. These gases when dissolved in water form corresponding binary acids. Four examples of formation of acidic gases by synthesis are given below:

1. Reaction of chlorine with hydrogen to form hydrogen chloride gas:

${\mathrm{H}}_2+{\mathrm{Cl}}_2\to 2\mathrm{HCl}$

2. Reaction of iodine with hydrogen to form hydrogen iodide gas:

${\mathrm{H}}_2+{\mathrm{I}}_2\to 2\mathrm{HI}$

3. Reaction of bromine with hydrogen to form hydrogen bromide gas:

${\mathrm{H}}_2+{\mathrm{Br}}_2\to 2\mathrm{HBr}$

4. Reaction of sulphur with hydrogen to form hydrogen sulphide gas:

${\mathrm{H}}_2+\mathrm{S}\to {\mathrm{H}}_2\mathrm{S}$
Note: The solution of hydrogen sulphide is a weak acid.