Chapter 15 - Haloalkanes

Question 1

Define ‘Nucleophile’

Answer 1

An electron pair donator

Question 2

What makes the Carbon - halogen bond polar?

Answer 2

1. Halogen atoms are more electronegative than the carbon atoms
2. This means that the electron pair is drawn closer to the halogen atom rather than the carbon atom

Question 3

Define ‘Substitution Reaction’

Answer 3

Is where one atom or group of atoms are replaced by another atom or group of atoms

Question 4

How can haloalkanes be converted into alcohols?

Answer 4

Reagent: NaOH
Conditions: Heat under reflux

Question 5

What is the carbon - halogen bond strength from weakest to strongest?

Answer 5

1. C - I
2. C - Br
3. C - Cl
4. C - F

Question 6

What is the general equation for the reaction of a primary haloalkane with water?

Answer 6

Primary haloalkane + H20 = Primary Alcohol + H+ + X-

Question 7

What is the equation with silver and the halide to form a silver halide?

Answer 7

Ag+(aq) + X-(aq) = AgX(s)

Question 8

Why is an ethanol solvent added to the experiment of the hydrolysis of primary haloalkanes?

Answer 8

Because haloalkanes are insoluble in water. Ethanol allows water and the haloalkane to mix and produce one single solution rather than 2 layers

Question 9

Hydrolysis of haloalkanes experiment:

Answer 9

1. In 3 seperate test tubes and 1cm3 of ethanol and 2 drops of the haloalkanes
2. Stand the test tubes in a water bath at 60 degrees
3. Add a test tube containing 0.1 mol dm-3 silver nitrate in the water bath
4. Quickly add 1cm3 of the silver nitrate quickly into the test tubes and start a stop clock
5. Stop the times when a colour change emerges

Question 10

What is the observation of the hydrolysis of 1-chlorobutane?

Answer 10

A white precipitate forms slowly

Question 11

What is the observation of the hydrolysis of 1-bromobutane?

Answer 11

A cream precipitate forms slower than 1-iodobutane but faster than 1-chlorobutane

Question 12

What is the observation of the hydrolysis of 1-iodobutane?

Answer 12

A yellow precipitate forms rapidly

Question 13

What is the trend between the rate of hydrolysis and the carbon-halogen bond?

Answer 13

The rate of hydrolysis increases as the strength of the carbon-halogen bond decreases

Question 14

Uses of CFCs and HCFCs

Answer 14

1. Refrigerants
2. Aerosol propellants
3. Solvents
4. Pesticides
5. Air-conditioners

Question 15

Properties of CFCs

Answer 15

1. Non-toxic
2. Low reactivity