Alcohols

Question 1

What is meant by the functional group and how does it apply to alcohols?

Answer 1

The group of atoms responsible for the characteristic reactions of a compound. For alcohols is the -OH hydroxyl group.

Question 2

What means that alcohols have a higher boiling/melting point than alkanes?

Answer 2

Alcohols contain hydrogen bonding which is must stronger than the permanent dipole dipole attractions in alkanes.

Question 3

What does the solubility of an alcohol depend on?

Answer 3

• The bigger the alcohol molecule, the less soluble they are in water.
• Solubility decreases as the hydrocarbon chain increases in size as the OH group has less influence and the solubility (or lack of) of the longer hydrocarbon chain becomes more dominant.

Question 4

What’s the mechanism for alcohols that you need to know (but don’t need to draw)?

Answer 4

Elimination
Called a reflux reaction and the dehydrating agent is either concentrated H2SO4 or concentrated H3PO4 as a catalyst.
Goes from alcohol to alkene + water.

Question 5

What’s the reactant when we oxidise an alcohol?

Answer 5

Acidified potassium dichromate(VI) K2Cr2O7