Mechanisms and Reactions

Question 1

Hydrogenation of alkenes

Answer 1

• Alkene + Hydrogen –> Alkane
• Electrophilic addition
• Nickel catalyst (423 K)

Question 2

Halogenation of alkenes

Answer 2

• Alkene + Halogen –> Haloalkane
• Electrophilic addition
• Room temp

Question 3

Hydration of alkenes

Answer 3

• Alkene + water –> alcohol
• Electrophilic addition
• Phosphoric acid catalyst

Question 4

Preparation of carboxylic acids

Answer 4

• Primary Alcohol + oxidising agent –> carboxylic acid
• Oxidation
• Reflux: K2Cr2O7 / H2SO4

Question 5

Preparation of aldehydes

Answer 5

• Primary Alcohol + oxidising agent –> aldehyde
• Oxidation
• Gentle heating: K2Cr2O7 / H2SO4

Question 6

Preparation of ketones

Answer 6

• Secondary Alcohol + oxidising agent –> ketone
• Oxidation
• Reflux: K2Cr2O7 / H2SO4

Question 7

Testing for unsaturation

Answer 7

• Alkene + bromine water –> Bromoalkane
• If alkene, orange colour dissapears
• Bromine added across double bond