Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. (A) is

Hydrocarbon (A) reacts with bromine by substitution to form an alkyl b

1.	Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. (A) is
Answer» `CH-=CH` `CH_2=CH_2` `CH_3-CH_3` `CH_4` Solution :(i)Since hydrocarbon (A) reacts with `Br_2` by substitution by form an alkyl bromide , THEREFORE , hydrocarbon (A) must be either `CH_4` or `CH_3CH_3` and the alkyl bromide it forms must be either `CH_3Br` or `CH_3CH_2Br` `CH_4+Br_2 overset"hv"to CH_3Br+HBr` `CH_3-CH_3+Br_2 overset"hv"to CH_3CH_2Br + HBr` (II) Since `CH_2=CH_2` and `CH-=CH` GIVE addition REACTIONS on treatment with `Br_2` , therefore , hydrocarbon (A) cannot be `CH_2=CH_2` or `CH-=CH`. (iii)Since alkyl bromide on Wurtz reaction gives a hydrocarbon containing less than four carbon atoms, therefore, alkyl halide must be `CH_3Br` and the hydrocarbon formed must be ETHANE. `2CH_3Br + 2Na underset"(Wurtz reaction)"oversetDeltato underset"Ethane"(CH_3-CH_3)+ 2NaBr`