Alcohols

Question 1

Reaction of alcohol + oxygen

Answer 1

alcohol + oxygen –> carbon dioxide + water

Question 2

Chlorination of alcohols

Answer 2

Reagent: solid PCl5
CH3CH2OH + PCl5 –> POCl3 + CH3CH2Cl + HCl

Question 3

Bromination of alcohols

Answer 3

Reagent: 50% H2SO4 + KBr + Heat under reflux
Step 1: KBr + H2SO4 –> HBr + KHSO4
Step 2: HBr + CH3CH2OH –> CH3CH2Br + H2O

Question 4

Iodination of Alcohols

Answer 4

Reagent: warm mixture with Damp Red Phosphorus + I
2P + 3I2 –> 2PI3
PI3 + 3CH3CH2OH –> 3CH3CH2I + H3PO3

Question 5

Oxidation of alcohols

Answer 5

Conditions: distillation (ketones), reflux (c.acids and aldehydes)
Reagent: Acidified Potassium Dichromate

1° oxidises to ketones then carboxylic acid

2° oxidises to aldehydes

Question 6

Formation of alkenes from alcohols

Answer 6

Conditions:
1. Hot Aluminium oxide catalyst
2. Concentrated phosphoric acid and warmed

Question 7

Test for alcohols

Answer 7

Add PCl5 –> tests OH group
Steamy fumes of HCl

Litmus test on blue –> turns red

Warm with acidified potassium dichromate turns orange to green