Alkanes

  • O/N 2021/P11/Q36

The structure of compound X is shown.

Four statements are made about compound X.

1 X burns in air to form carbon dioxide and water.

2 X turns bromine water from colourless to brown.

3 X is propene.

4 The number of C–C single bonds is increased by reacting X with hydrogen.

Which statements are correct?

A  ​​​​ 1 and 2  ​​ ​​​​ B ​​ 1 and 4  ​​ ​​​​ C ​​ 2 and 3  ​​ ​​​​ D ​​ 3 and 4​​ 

 

Answer: ​​ D

Explaination

Alkanes are saturated hydrocarbons because of C-C single bond. There viscosity increases down the series as the C chain grows longer and heavier. Alkanes react with chlorine​​ or bromine in substitution reaction not in addition reaction. As their general formula is CnH2n+2​​ so here for C35H72​​ we put n=35 to get the correct answer like this:

CnH2n+2

C(35)H2(35)+2 ​​ =​​ C35H72