Question

Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.

Answer 1

Saturated hydrocarbons:-

1. A hydrocarbon where there is only the presence of only single bond between the carbons atoms is called saturated hydrocarbon.
2. They are also called alkanes
3. The general formula for saturated hydrocarbons are${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+2}$.
4. Some examples include: Propane $({\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_3)$, Butane $({\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_3)$

Unsaturated hydrocarbons:-

1. A hydrocarbon where there is the presence of a double or triple bond between the carbons atoms is called an unsaturated hydrocarbon.
2. They are also called alkenes and alkynes.
3. The general formula for unsaturated hydrocarbons are${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}-2}$(alkenes), ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}$(alkynes)
4. Some examples include: Propene $({\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2)$, But-1-yene $({\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{C}\equiv \mathrm{CH})$

Test to differentiate between saturated and unsaturated hydrocarbons:-

1. We use the bromine water test in order to distinguish between saturated and unsaturated hydrocarbon.
2. Bromine water is nothing but bromine water.
3. When bromine water is treated with unsaturated hydrocarbons, the bromine gets attached to hydrocarbon and thus the red-brown colour of bromine gets decolourised.
4. On the other hand, when bromine water is reacted to saturated compounds, the red-brow colour of bromine remains the same.

Therefore, to differentiate between saturated and unsaturated hydrocarbons, we can use the bromine water test.