Organic func. group tests

Question 1

test for alkene

Answer 1

bromine water

orange -> colourless

Question 2

test for alcohol + carboxylic acid

Answer 2

PCl5 (chlorination of alcohols = HCl + POCl3)

misty fumes of HCl produced

Question 3

test for alcohols, phenols and carboxylic acids

Answer 3

sodium metal

efferversence due to H2 gas

Question 4

test for carbonyls (C=O in ketones/ aldehydes )

Answer 4

2,4- DNP

orange/ red crystals produced

Question 5

test for aldehydes (F)

Answer 5

fehling’s
heat gently
blue solution to red ppt

KETONES DO NOT REACT

Question 6

test for aldehydes (T)

Answer 6

tollen’s reagent
heat gently
silver mirror forms

KETONES DO NOT REACT

Question 7

test for carboxylic acid

Answer 7

Na2CO3

effervescence of CO2

Question 8

test for primary + secondary alcohol and aldehyde

Answer 8

Na2Cr2O7

orange to green

Question 9

test for chloroalkane

Answer 9

warm with silver nitrate (+ dil nitric acid)

ppt of AgCl forms

Question 10

test for acyl chlorides

Answer 10

AgNO3

(EQ: Add nitric acid to remove any carbonate and halide ions)

Vigorous reaction= steamy fumes of HCl and white ppt of AgCL