Compound 'X' is bubbled through bromine dissolved in CCl₄ and the product formed is CH₂Br – CH₂Br.

i) Draw the structural formula of 'X' and state what type of reaction 'X' has undergone.

(ii) State your observation for the above reaction.

(iii) Name the compound formed when steam reacts with 'X' in the presence of an acid, eg. phosphoric acid.

(iv) What is the procedure for converting the product formed in (iii) above, back to 'X' ?

(i) Compound 'X' is Ethene (H₂C=CH₂). Its structural formula is shown below:

Ethene [CH₂=CH₂] has undergone addition reaction.

(ii) Brown colour of bromine is discharged.

(iii) Ethanol

$\underset{\text{Ethene}}{\text{C}$2\text{H}4} + \underset{\text{ water} }{\text{H}2\text{O}} \underset{\text{acid}}{\xrightarrow{\text{H}}^+} \underset{\text{ ethanol} }{\text{C}2\text{H}_5\text{OH}}

(iv) Ethanol can be converted into ethene, by dehydrating it with concentrated H₂SO₄ at 170°C.

$\underset{\text{ ethyl alcohol}}{\text{C}$2\text{H}5\text{OH}} \xrightarrow[170\degree\text{C}]{\text{Conc. H}2\text{SO}4\text{[excess]}} \underset{ \text{ethene}}{\text{C}2\text{H}4} + \text{H}_2\text{O}\