Test-tube reactions Flashcards
1
Q
How do you test for alcohols?
A
Add acidified potassium dichromate (Kr2Cr2O7). Warm gently.
Orange to green if primary and secondary alcohols. Stays orange if tertiary alcohols
2
Q
How do you test for aldehydes?
A
Add Tollen’s reagent and warm gently. Silver mirror if aldehyde present. If colourless, most likely ketone
3
Q
How else do you test for aldehydes?
A
Add Fehling’s solution and heat. Brick red precipitate if aldehyde present, stays blue and no ppt if not
4
Q
How do you test for alkenes?
A
Decolourises bromine water (orange to colourless)
5
Q
How do you test for carboxylic acids?
A
Add sodium carbonate (Na2CO3) to sample, if carboxylic acid is present the solution will fizz and produce CO2. Bubble gas through limewater to test for CO2, cloudy = positive
