tests for ions and functional groups

Question 1

what is the test for a haloalkane and the results?

Answer 1

• add NaOH and warm in a waterbath
• ethanol solvent
• AgNO3

observations:
Cl = white ppt
Br = cream ppt
I = yellow ppt

Question 2

what is the test for an alkene and the result ?

Answer 2

• decolourises bromine water

Question 3

what is the test for a phenol and the result?

Answer 3

• add bromine water
• decolourises and a white ppt is formed

Question 4

what is the test for a carboxylic acid and the result?

Answer 4

• add a carbonate e.g. NaCO3
• effervescence
• gas turns limewater cloudy

Question 5

what is the test for a carbonyl group (aldehyde or ketone) and the result?

Answer 5

• add 2,4 - DNPH
• orange/yellow precipitate formed

Question 6

what is the test for an aldehyde and the result?

Answer 6

• tollen’s reagent
• silver mirror formed

Question 7

what two tests are needed together to show that a ketone is present and what are the results?

Answer 7

• 2,4- DNPH will form an orange precipitate
• tollen’s reagent, no silver mirror forms

Question 8

what is the test for a carbonate and what is the result?

Answer 8

• add a carboxylic acid
• effervescence

Question 9

what is the test for a sulphate and what is the result?

Answer 9

• barium nitrate added
• white precipitate formed

Question 10

what is the test for ammonium and the result?

Answer 10

• NaOH solution
• warm in a waterbath
• damp red litmus paper turns blue due to ammonia gas

Question 11

what is the test for H+ ions (inorganic acid) and the result?

Answer 11

• add a carbonate e.g. NaCO3
• effervescence
• gas turns limewater cloudy