Tests Flashcards
Test for double bond
Few drops of bromine water ( redish brown colour )
If it has a double bond it goes colourless
Tollens test
Silver mirror
Solution of silver nitrate in aqueous ammonia
Silver mirror formed if its an aldehyde
[ Ag(NH3)2]+ + e- ➡️ Ag + 2NH3
Fehlings test
Blue copper (ll) ions to a red precipitate copper (i) ion
Oxides aldehydes
Cu 2+ + e- ➡️ Cu+
Halogenalkane
R-X
Add NaOH and warm
Acidify with HNO3
Add AgNO3
Precipitate of AgX
Alcohol
R-OH
Acidified K2Cr2O7
Orange to green colour
Primary alcohols
Secondary alcohols
Aldehydes
Carboxylic acid
Add NaHCO3
Carbon dioxide given off
Barium chloride and NaOH
Initial = colourless solution
NaOH = colourless solution
Excess NaOH = colourless solution
Calcium bromide and NaOH
Initial = colourless solution
NaOH = slight white ppt
Excess NaOH = slight white ppt
Magnesium chloride and NaOH
Initial = colourless solution
NaOH = slight white ppt
Excess NaOH = white ppt
Strontium chloride and NaOH
Initial = colourless solution
NaOH = slight white ppt
Excess NaOH = slight white ppt
Barium chloride and H2SO4
Initial = colourless solution
H2SO4 = white ppt
Excess H2SO4 = white ppt
Calcium bromide and H2SO4
Initial = colourless solution
H2SO4 = slight white ppt
Excess H2SO4= slight white ppt
Magnesium chloride and H2SO4
Initial = colourless solution
H2SO4 = slight white precipitate
Excess H2SO4 = colourless solution
Strontium chloride and H2SO4
Initial = colourless solution
H2SO4 = white ppt
Excess H2SO4 = white ppt
Ammonium chloride and sodium hydroxide
Damp red litmus paper = blue