Organic: test tube reactions (RP 6)

Question 1

How would you test for an alcohol?

Answer 1

Add acidified potassium dichromate to organic compound. Turns from orange to green if primary or secondary alcohol is present

Question 2

How do you test for an alkene?

Answer 2

Decolourises bromine water

Question 3

How do you test for a carboxylic acid?

Answer 3

Add sodium carbonate to organic compound and collect gas produced. Effervescence. Bubble gas through limewater and limewater should turn cloudy if present.

Question 4

How do you test for an aldehyde?

Answer 4

1. Add fehlings solution. Brick red precipitate will form if present.
2. Add tollens reagent. Heat. Silver mirror forms if present

Question 5

How do you distinguish between an aldehyde and a ketone?

Answer 5

Ketones have no reaction with fehlings and tollens

Question 6

How do you test for a halogenoalkane?

Answer 6

Add sodium hydroxide. Add nitric acid to remove any carbonate ions. Add silver nitrate. White ppt forms if present