Organic

Question 1

Initiation reaction

Answer 1

UV light provides enough energy to break halogen bonds in homolytic fission
Free radicals formed

Question 2

Propagation reaction

Answer 2

Radical attacks a molecule taking the hydrogen molecule
New radical formed can attack halogen
Happens until all halogens and alkanes used up

Question 3

Termination reaction

Answer 3

2 radicals join to form a stable molecule

Question 4

Problem of free radical substitution

Answer 4

Hard to make a particular product without getting a mixture
Mixture of isomers can form
React in excess alkane so greater chance of collision with halogen

Question 5

Sigma bond

Answer 5

Bond when 2 s orbitals overlap in a straight line giving the highest possible electron density

Question 6

Affect if high electron density

Answer 6

Means strong electrostatic attraction between the nuclei and shared pair of electrons
High bond enthalpy

Question 7

Pi Bond

Answer 7

Sideways over lap of 2 adjacent p orbitals, one above and one below the molecular axis as dumb bell shaped
Electron density shared above and below

Question 8

Why are alkanes more reactive

Answer 8

Alkanes have sigma bonds and are non polar so don’t attract nucleophiles and electrophiles
Alkenes have sigma bonds which have high electron density with the 4 electrons and pi bond stocks out above and below molecule so likely to be attacked by electrophiles

Question 9

Stereoisomers

Answer 9

Have same structural formula but different arrangement in space

Question 10

Primary alcohols oxidised

Answer 10

Into aldehydes and then to carboxylic acids

Question 11

Secondary alcohol oxidation

Answer 11

Oxidised to ketones

Question 12

Tertiary alcohol oxidation

Answer 12

Not oxidised