Compound A is bubbled through bromine dissolved in carbon tetrachloride and the product formed is CH₂Br–CH₂Br.

(i) Draw the structural formula of A.

(ii) What type of reaction has A undergone.

(iii) What is your observation.

(iv) Name (not formula) the compound formed when steam reacts with A in the presence of phosphoric acid.

(v) What is the procedure for converting the product of (e) (iv) back to A ?

(i) Compound A is Ethene (H₂C=CH₂). It's structural formula is shown below:

(ii) Ethene [CH₂=CH₂] has undergone addition reaction.

(iii) Brown colour of bromine is discharged.

(iv) 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}}

(v) 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}\