4.2.2 - Haloalkanes

Question 1

nucleophile

Answer 1

electron pair donor

Question 2

nucleophilic substitution of haloalkanes

Answer 2

• hydrolysis by aqueous alkali NaOH
• halogen atom replaced by -OH group
• carbon-halogen bond breaks by heterolytic fission
• forms an alcohol and a halide ion

Question 3

carbon-halogen bond strength

Answer 3

• strongest: C-F bond
• weakest: C-I bond
• need less energy to break C-I bond

Question 4

experiment to compare rates of hydrolysis

Answer 4

• hydrolysis with water
• in the presence of AgNO₃ and ethanol
• halide ions produced react with silver ions to form a precipitate
• ethanol allows water and haloalkane to mix
• rate of hydrolysis increases as carbon-halogen bond strength decreases

Question 5

breakdown of ozone

Answer 5

photodissociation (homolytic fission, requires UV):
CF₂Cl₂ → CF₂Cl• + •Cl

•Cl + O₃ → •ClO + O₂
•ClO + O → •Cl + O₂

Question 6

breakdown of ozone by other radicals

Answer 6

NO• + O₃ → NO₂• + O₂
NO₂• + O → NO• + O₂