6.3.1 - Chromatography and Qualitative Analysis

Question 1

test for alkenes

Answer 1

• bromine water
• decolourised
• orange → colourless

Question 2

test for haloalkanes

Answer 2

• acidified silver nitrate
• white/cream/yellow precipitates
• confirm with ammonia

Question 3

test for carbonyls

Answer 3

• 2,4-DNP
• orange precipitate

Question 4

test for aldehydes

Answer 4

• Tollens’ reagent
• silver mirror

Question 5

test for 1°/2° alcohols/aldehydes

Answer 5

• acidified potassium dichromate(VI)
• orange → green

Question 6

test for carboxylic acids

Answer 6

• metal carbonate
• effervescence (CO₂)

Question 7

test for phenols

Answer 7

• weak acidity
• no reaction with carbonates