Identification Of Alcohols And Phenols

Question 1

What is the structure of alcohols and phenols?

Answer 1

Alcohols: (R-OH)

Phenols: (Benzene-OH)

Question 2

What are the classifications of alcohols?

Answer 2

1) primary alcohols 1* (the carbon bearing the hydroxyl group has one alkyl group)

2) secondary alcohols 2* (the carbon bearing the hydroxyl group has two alkyl groups)

3) tertiary alcohols 3* (the carbon bearing the hydroxyl group has three alkyl groups)

Question 3

What are the physical properties of the alcohols and phenols?

Answer 3

They contain a polar group which enables them to form hydrogen bonds, thus they can mix with water, they are soluble in many organic solvents such as dichloromethane and diethyl ether

Question 4

How can ferric chloride (FeCl3) identify alcohols and phenols?

Answer 4

It can detect phenols by giving a green to purple color ((Benzene-O)3Fe) + 3HCl

Question 5

How can the chromic test (H2CrO4/H2SO4) identify alcohols and phenols?

Answer 5

It distinguishes primary and secondary alcohols from tertiary alcohols, giving a green product with 1* & 2* as it oxidizes them and no color change with 3* as it doesn’t get oxidized

Question 6

How can Lucas test (ZnCl2/HCl) identify alcohols and phenols?

Answer 6

Used to distinguish between 1,2, & 3* alcohols

1* doesn’t react
2* reacts slowly after heating to give cloudiness
3* reacts immediately forming cloudiness