G10 Chemistry - Tests

Question

Answer

Test for hydrogen gas

Insert a lit splint → squeaky pop sound

Test for oxygen gas

Insert a glowing splint → relights

Test for carbon dioxide gas

Bubble through limewater → turns milky/cloudy

Test for ammonia gas

Damp red litmus paper turns blue

Test for chlorine gas

Damp blue litmus paper is bleached white

How do you carry out a flame test?

Clean nichrome wire loop with HCl

Flame test colour for Li+

Red / crimson flame

Flame test colour for Na+

Yellow flame

Flame test colour for K+

Lilac flame

Flame test colour for Ca2+

Orange-red / brick-red flame

Flame test colour for Cu2+

Blue-green flame

Test for NH4+ (ammonium ion)

Add NaOH and warm → ammonia gas released (turns red litmus blue)

Test for Cu2+ with NaOH

Blue precipitate of Cu(OH)2

Test for Fe2+ with NaOH

Green precipitate of Fe(OH)2 (turns brown on standing)

Test for Fe3+ with NaOH

Brown precipitate of Fe(OH)3

Test for Cl- (chloride ion)

Add dilute HNO3

Test for Br- (bromide ion)

Add dilute HNO3

Test for I- (iodide ion)

Add dilute HNO3

Test for SO4^2- (sulfate ion)

Add dilute HCl

Test for CO3^2- (carbonate ion)

Add dilute HCl → effervescence