Test for alkene:
- Add bromine water and shake OR
- Add bromine in hexane and shake
- The colour changes from orange to colourless
- The colour changes from brown to colourless.
Test for alcohol group:
- Add dry PCl5
- Steamy white fumes which turn damp blue litmus paper red
Tests No. 2:
Test for halogenoalkane:
- Add aqueous NaOH and heat.
- Add excess dilute nitric acid and silver nitrate solution.
- Add dilute or concentrated aqueous ammonia.
With C-Cl (chloroalkane): A white precipitate forms which is soluble in dilute aqueous ammonia.
With C-Br (bromoalkane): A cream precipitate forms which is only slightly soluble in dilute aqueous ammonia/ soluble in concentrated aqueous ammonia.
With C-I (iodoalkane): A yellow precipitate forms which is insoluble in dilute aqueous ammonia/insoluble in concentrated aqueous ammonia.
Tests No. 3:
Test for primary/secondary/tertiary alcohols:
- Add potassium dichromate (VI) solution and dilute sulphuric acid and heat
- K2Cr2O7 solution + dilute H2SO4 + heat
- Add potassium manganate (VII) solution and dilute sulphuric acid and heat
- KMnO4 + dilute H2SO4 + heat
With primary alcohol: Orange to Green
With secondary alcohol: Orange to Green
With tertiary alcohol: Orange remains Orange
Tests No. 4:
Tests for aldehydes and ketone:
- Add-2,4-DNP (dinitrophenylhydrazine)
Observation with aldehydes and ketone:
- An orange precipitate is formed.
Tests for carboxylic acids:
- Add aqueous Na2CO3 or aqueous NaHCO3
Observation with carboxylic acids
- Effervescence is observed.
- A colourless gas forms which turns limewater cloudy.
Tests No. 5:
Tests for methyl secondary alcohols and methyl ketones:
- Add iodine and aqueous NaOH to the compound and heat.
Observation with methyl secondary alcohols and methyl ketones:
- A pale yellow precipitate of CHI3 is formed.
Test for aldehydes:
- Add Tollen's reagent (ammonical silver nitrate solution) and heat OR
- Add Fehling's solution and heat
Observations with aldehydes:
With Tollen's reagent: A silver mirror is formed with the aldehyde
With Fehling's solution: The blue solution turns to a red precipitate with the aldehyde.