GCE O Level Chem Qualitative Analysis Notes

Page | 1

Green

precipitate

turns brown

after

reaction

when left to

stand.

GCE O Level Chem Qualitative Analysis Notes

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White precipitate form, soluble in excess

Pb2+ 7.

White precipitate form, insoluble in

excess

8

+aq ammonia in excess

+aq NAOH in excess

GCE O Level Chem Qualitative Analysis Notes

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Gas Formula Colour Smell Litmus Paper Test Confirmatory Test

Hydrogen H2 X X Blue to red Red remains red

Extinguished lighted splint with a “pop”

sound

Oxygen O2 X X X Relights a glowing

splint

Chlorine Cl2 Greenish Pungent Blue turns red then

get bleaches.

Red get bleaches.

X

Carbon

Dioxide

CO2 X X Blue turns red

Red remains red

i) White Precipitate is

formed in lime water(Calcium

Hydroxide) ii) Extinguishes

lighted splint without any sound

Ammonia NH3 X Pungent Turns moist red

litmus paper blue

Turns moist red litmus

paper blue

Water Vapour

H2O X X X Turns blue cobalt chloride paper pink

Sulphur Dioxide

SO2 X Pungent Blue to red Red remains red

i) Turns Orange dichromate(VI) green

ii) Turns purple acidified paper

potassium manganate(VII)

colourless

Green

precipitate

turns

brown

after

reaction

when left to stand.

(+)

GCE O Level Chem Qualitative Analysis Notes

Page | 4

Add dilute nitric

acid, then add

barium nitrate

*An alternative for sulphate test, add HCl(aq) and BaCl2(aq) *An alternative for iodide test, add HCl(aq) and PbCl2(aq)