Tests For Functional Groups

Question 1

Test for alkene

Answer 1

Add bromine water drop-wise

Question 2

Observation for alkene test

Answer 2

Bromine water decolourised from orange to colourless

Question 3

Test for haloalkane

Answer 3

Add silver nitrate and ethanol and warm to 50C in a water bath

Question 4

Observation for haloalkane test

Answer 4

Chloroalkane - white precipitate
Bromoalkane - cream precipitate
Iodoalkane - yellow precipitate

Question 5

Test for carbonyl

Answer 5

Add 2,4-DNPH

Question 6

Observation for carbonyl test

Answer 6

Orange prepitate

Question 7

Test for aldehyde

Answer 7

Add Tollens’ reagent and warm

Question 8

Observation for aldehyde test

Answer 8

Silver mirror

Question 9

Test for primary/secondary alcohol and aldehyde

Answer 9

Add acidified potassium dichromate(VI) and warm in a water bath

Question 10

Observation for primary/secondary alcohol and aldehyde test

Answer 10

Colour change from orange to green

Question 11

Test for carboxylic acid

Answer 11

Add aqueous sodium carbonate

Question 12

Observation for carboxylic acid test

Answer 12

Effervescence