Chapter 14 - Properties of Alcohols

Question 1

What is the general formula of an Alcohol?

Answer 1

CnH2n+1OH

Question 2

Is an alcohol polar and why?

Answer 2

An alcohol is polar as it contains polar O-H bonds because oxygen is more electronegative than hydrogen. Therefore hydrogen bonds exist between the molecules.

Question 3

Melting and Boiling points of Alcohols?

Answer 3

High as there are strong hydrogen bonds.

Question 4

Solubility of Alcohols?

Answer 4

Alcohols can form hydrogen bonds with water molecules. Solubility decreases as the carbon chain length increases.

Question 5

When oxidising alcohols what oxidising agent is used?

Answer 5

Acidified Potassium Dichromate (VI) - K2Cr2O7/H2SO4

Question 6

What are primary alcohols oxidised to?

Answer 6

Aldehydes, RCHO, and carboxylic acids, RCOOH

To form aldehydes you heat with potassium dichromate and then distill.

To form the carboxylic acid you heat under reflux.

Question 7

What are secondary alcohols oxidised to?

Answer 7

Ketones, RCOR

Heated under reflux, and cannot be oxidised any further.

Question 8

What are tertiary alcohols oxidised to?

Answer 8

They cannot be oxidised.

Question 9

Elimination reactions of alcohols?

Answer 9

Dehydrating agents such as concentrated sulphuric acid, H2SO4, and phosphoric acid, H3PO4 can be used to remove H2O.

Question 10

Substitution reactions of alcohols?

Answer 10

Alcohols react with halide ions in acidic conditions. Hydrogen bromide reacts with alcohol and is substituted into the alcohol.