Chapter 14

Question 1

What are alcohols?

Answer 1

Alcohols are family of compounds with an OH functional (hydroxyl group)

Question 2

Are alcohols polar?

Answer 2

Alcohols are polar due to the electronegativity difference between the oxygen and hydrogen atoms.

Question 3

Can alcohols form hydrogen bonds?

Answer 3

Yes they are able to form hydrogen bonds between the hydrogen and oxygen of other alcohols.

Question 4

Are alcohols soluble?

Answer 4

Alcohols are soluble because hydrogen bonds are able to form between the water molecules and the OH group.

Question 5

Do alcohols have a higher or lower voltality than alkanes and alkenes?

Answer 5

Alcohols have a lower voltality (higher boiling point) due to the strong intermolecular hydrogen bonds which take a lot of energy to break

Question 6

How can you classify alcohols as primary, secondary and tertiary?

Answer 6

Primary alcohols have one carbon atom bonded to the carbon atom with the functional group, secondary two and tertiary three.

Question 7

Explain how primary alcohols are oxidised

And draw equations for each reaction

Answer 7

Primary alcohols can be oxidised to either aldehydes or carboxylic acids
To form aldehydes the primary alcohol must must be heated gently with acidified potassium dichromate in distillation apparatus to ensure the aldehyde formed is distilled out as soon as it is formed. The dichromate ions will will turn from orange to green.
To form a carboxylic acid the primary alcohol must be heated vigorously under reflux with acidified potassium dichromate to ensure any aldehyde produced is oxidised to form a carboxylic acid.

Question 8

Explained how secondary alcohols are oxidised

And draw equations for each reaction

Answer 8

Secondary alcohols are oxidised to ketones under reflux with acified potassium dichromate
The dichromate ions will turn from orange to green

Question 9

Explain how tertiary alcohols are oxidised

Answer 9

Tertiary alcohols do not oxidise as the carbon that is bonded to the functional group is bonded to three other carbon atoms so cannot form a double bond as carbon can only form four bonds

Question 10

Explain the substitution of alcohols

And draw the equation

Answer 10

An alcohol is heated under reflux with sulfuric acid and a sodium halide, a hydrogen halide is formed in situ ( in place). The alcohol reacts with the hydrogen halide to form an alkane and water.

Question 11

Explain the dehydration of alcohols

And draw the equation

Answer 11

An alcohol is heated under reflux with an acid catalyst (H2SO4) to form an alkene and water