14.1 - Properties of Alcohols

Question 1

What is the alcohol functional group?

Answer 1

Hydroxyl - OH

Question 2

What are the uses of methanol and ethanol?

Answer 2

Methanol - chemical feedstock

Ethanol - alcoholic drinks, fuels, solvent in feedstock

Question 3

How should the alcohol CH3CCH3(OH)CH(OH)CH3 be named?

Answer 3

2-methybutane-2,3-diol

not butan-2,3-diol as the suffix (diol) begins with a consonant not a vowel.

Question 4

What are the physical properties of alcohols?

Answer 4

• Polar O-H bond due to difference in electronegativity
• Less volatile than alkanes of the same Mr or chain length
• Higher bp than equivalent Mr or chain length alkanes due to London forces and H-bonds requiring more energy to be broken.

Question 5

What is volatility?

Answer 5

Tendency of a substance to evaporate

Alcohols have a low volatility than equivalent alkanes due to the higher bp.

Question 6

What is the water solubility of alcohols?

Answer 6

Since water can form hydrogen bonds/London forces with water molecules, they are completely soluble in water, unlike alkanes which cannot form hydrogen bonds with water.

Question 7

In terms of taking and releasing energy, what is the difference between bond making and bond breaking?

Answer 7

Bond making: release energy

Bond breaking: take in energy

Question 8

How do you classify alcohols as primary, secondary or tertiary?

Answer 8

Primary - hydroxyl that is bonded to a carbon with 1 R group attached

Secondary - hydroxyl that is bonded to a carbon with 2 R groups attached

Tertiary - hydroxyl that is bonded to a carbon with 3 R groups attached