Organic Tests Flashcards
(8 cards)
How to test for alcohols aldehydes and ketones with acidified potassium dichromate and what are the results
Add acid and then potassium dichromate to the solution
Alcohol - orange to green solution for primary and secondary. Tertiary stays orange
Aldehyde - bright orange to green
Ketone - no reaction as ketones don’t oxidise further
How to test for alcohols aldehydes and ketones with acidified permanganate (KMnO4-) and what are the results
Add acid then add permanganate to the solution
Alcohol - purple to colourless solution
Aldehyde - purple to colourless solution
Ketone - no reaction
How to test for alcohols aldehydes and ketones with Fehlings solution and what are the results
Mix equal vol of fehling’s solution B and A.
Add 5 drops of test reagent to 1cm3 of sodium carbonate with anti bumping granules and then add 1cm3 of Ethan Allen
Warm gently for 2 mins then bring and maintain the beaker at boiling for a few minutes
Lift the test tube
Alcohol - no reaction
Aldehyde - blue solution to orange-red ppt
Ketone - no reaction
How to test for alcohols aldehydes and ketones with Tollens reagent and what are the results
5 drops of sodium hydroxide to 2cm3 of silver nitrate
Add just enough dilute ammonia to dissolve the brown ppt
Gently warm 5cm3 of the reagent at 50 degrees celsius
10 drops of distillate containing ethanal and wait a few minutes and see what happens
Alcohol - no reaction
Aldehyde - silver ppt on sides of test tube
Ketone - no reaction
How to test for alcohols aldehydes and ketones with sodium metal and what are the results
Add small piece to ethanol in a dry test tube
Alcohol - hydrogen has given off and a colourless solution produced
Aldehyde - no reaction
Ketone - no reaction
How do you test for saturation in an organic substance? What are the results ?
Add 2 drops of cyclohexane in a test tube add about 1cm3 of bromine water and shake vigorously
Alkene goes colourless and alkane stays orange
How do you test for a halogenoalkane and what are the results
5 drops of 1-bromobutane to 1cm3 of sodium hydroxide. Warm contents for a few minutes in a beaker of 50 degrees Celsius water
Acidify the contents by adding 2cm3 of dilute nitric acid and add 1cm3 of silver nitrate
In AgCl white ppt
AgBr cream ppt
AgI yellow ppt
How do you test for a carboxylic acid and what are the results?
One small spatula for f sodium hydrogen carbonate in test tube and add it to 2cm3 of dilute ethanoic acid
Bubbling occurs
