Tests for functional groups

Question 1

Test for alkene

Answer 1

add bromine water - orange to colourless

Question 2

Test for primary/secondary alcohol

Answer 2

warm with acidified potassium dichromate - orange to green

Question 3

Test for aldehyde

Answer 3

warm with Tollen’s reagent - silver mirror (precipitate)

Question 4

Test for aldehyde 2

Answer 4

warm with Fehling’s solution - red precipitate

Question 5

Test for chloroalkane

Answer 5

warm with silver nitrate in ethanol - white precipitate

Question 6

Test for bromoalkane

Answer 6

warm with silver nitrate in ethanol - cream precipitate

Question 7

Test for iodoalkane

Answer 7

warm with silver nitrate in ethanol - yellow precipitate

Question 8

Test for carboxylic acid

Answer 8

add sodium carbonate or sodium hydrogen carbonate - bubbles of CO2 - white ppt with limewater

Question 9

Test for carboxylic acid 2

Answer 9

add magnesium - hydrogen produced - squeaky pop

Question 10

Inference if Tollen’s reagent does not produce a silver mirror

Answer 10

ketone present (not aldehyde)

Question 11

Inference if Fehling’s solution remains blue

Answer 11

ketone present (not aldehyde)

Question 12

Inference if alcohol does not turn potassium dichromate from orange to green

Answer 12

tertiary alcohol