Question

Ethene decolorizes _ water.

• A. bromine
• B. distilled

Answer 1

The organic compounds containing Carbon $\left(\mathrm{C}\right)$ atoms having double bonds between two Carbon atoms are called unsaturated hydrocarbons.

Ethene $\left({\mathrm{C}}_2{\mathrm{H}}_4\right)$ contains double bonds between the Carbon atoms so it is an unsaturated hydrocarbon.

Bromine water test:

Ethene changes the color of the solution from reddish-orange color to a colorless solution with the addition of Bromine $\left(\mathrm{Br}\right)$ water.

The reaction of Ethene with Bromine molecule can be written as:

$$\begin{gathered} {\mathrm{CH}}_2={\mathrm{CH}}_2+\mathrm{Br}-\mathrm{Br}\to {\mathrm{BrCH}}_2-{\mathrm{CH}}_2\mathrm{Br} \\ \left(\mathrm{Ethene}\right)\left(\mathrm{Bromine}\right)(1,2-\mathrm{dibromoethane}) \end{gathered}$$

Ethene decolorizes Bromine water.