practical 6- paper 2+3--> alcohol, aldehydes, alkene and carboxylic acid test

Question 1

test for alkenes

Answer 1

bromine water
orange to colourless
reason: electrophilic addition of Br2 to alkene

Question 2

test for primary, secondary alcohols and aldehydes

Answer 2

acidified K2Cr2O7
orange to green
reason: Cr2O72- (orange) is reduced to Cr3+ (green) when oxidized

Question 3

test for aldehydes

Answer 3

tollen’s reagent: silver mirror
reason: Ag+ in tollens reagent is reduced to Ag when aldehyde is oxidised
Fehling’s solutions : brick red ppt
reason: Fehling’s solution reduced when aldehyde is oxidised

Question 4

test for carboxylic acid

Answer 4

sodium carbonate- effervescence
reason: formation of CO2