Crude oil contains a large proportion of alkanes, which form a homologous series

ID: 782604 • Letter: C

Question

Crude oil contains a large proportion of alkanes, which form a homologous series.

(i) Explain the meaning of the term homologous series, using the alkanes as your example.

(ii) Alkanes exhibit structural isomerism. Draw the structural formulae of the three structural isomers of the alkane C5 H12.

bMethane reacts with chlorine in the presence of ultraviolet light to give chloromethane and hydrogen chloride:

(i) What type of reaction is this?

(ii) The first step of the mechanism involves homolytic fission. Explain the meaning of the term homolytic fission. (1 mark)

(iii) Give the mechanism for the reaction between methane and chlorine, making clear which are the initiation, propagation and termination steps.

(i) Homologous series is a family of organic compounds with similar chemical properties, for e.g. alkanes is flammable.

(ii) Can be searched on internet

(b)(i) Free radical substitution reaction

(b)(ii) The breaking of a bond of compound in which the atoms are uncharged free radicals.

(b)(iii)

1. Initiation

Uv light breaks Cl-Cl bond to form Cl free radicals

2. Propagation

Free radical chlorine atom breaks bonds between methane, replacing hydrogen atom. (Random event)

3.Termination

The reaction stops when there is no more radicals, stopping reaction.

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.