Alcohol Reactions

Question 1

Alcohol Reactions

Answer 1

Oxidation (combustion)
Oxidation
Condensation (esterification)

Question 2

Alcohol oxidation (combustion)

Answer 2

Alcohol + Oxygen –> Carbon Dioxide + Water + Energy

Conditions: None

Question 3

Alcohol oxidation (combustion) example ( C2H5OH + 3O2 )

Answer 3

C2H5OH + 3O2 –> 2CO2 + 3H2O
Negative enthalpy in products

Conditions: None

Question 4

Alcohol oxidation

Answer 4

Primary alcohol + Oxidising agent –> Aldehyde
Aldehyde + Oxidising agent –> Carboxylic acid

Conditions: Acidic (H+), Oxidising agent (Potassium dichromate (K2CR2O7), Potassium manganate), heat

• Secondary alcohols form ketones, while primary alcohols form aldehydes.

Question 5

Alcohol oxidation example ( C2H5OH )

Answer 5

C2H5OH –> C2H4O
C2H4O –> C2H3OOH

Conditions: Acidic (H+), Oxidising agent (Potassium dichromate, Potassium manganate)

Question 6

Alcohol condensation (esterification)

Answer 6

Alcohol + Carboxylic Acid –> Ester + Water

Conditions: Acidic (H+), heat

Question 7

Alcohol condensation (esterification) example ( C2H3OOH + C2H5OH )

Answer 7

C2H3OOH + C2H5OH –> C4H8OOH + H2O

Conditions: Acidic (H+), heat

Question 8

Determination of primary, secondary, tertiary alcohols

Answer 8

By using a strong oxidising agent (potassium permanganate or acidified potassium dichromate) different colour changes can be seen.

Primary alcohols: react to form an aldehyde then a carboxylic acid. Colour change from yellow to green.

Secondary alcohols: React to form a ketone but not a carboxylic acid. Colour change from yellow to green.

Tertiary alcohol: Do not react. Solution remains yellow