G) Chemical tests

how to test for hydrogen

how to test for hydrogen

squeaky pop with lit splint

how to test for oxygen

relight a smoldering splint

how to test for carbon dioxide

bubble through limewater

colourless —> cloudy

how to test for ammonia

add sodium hydroxide

will turn moist litmus paper from red to blue, and moist universal indicator paper to blue

how to test for chlorine

damp blue litmus paper will turn to red and then to white

flame test for Lithium

Li⁺

red

flame test for Sodium

Na⁺

yellow

flame test for potassium

K⁺

Lilac

flame test for calcium

Ca²⁺

orange-red

flame test for copper

Cu²⁺

blue-green

iron (II) + sodium hydroxide

Fe²⁺ + NaOH

green precipitate

iron (III) + sodium hydroxide

Fe³⁺ + NaOH

brown precipitate

copper + sodium hydroxide

Cu²⁺ + NaOH

blue precipitate

ammonium + sodium hydroxide

NH₄⁺ + NaOH

Gas → red litmus blue

how to test for sulfate using hydrochloric acid and acidified barium chloride solution

SO₄^2- + HCl

SO₄^2- + BaCl₂

add HCl to remove any impurities

add BaCl₂ solution → if sulfate ions are present, a white precipitate will form

how to test for carbonate using hydrochloric acid and identifying the gas evolved

CO₃^2-

if carbonate ions are present, fizzing will occur

carbon dioxide is evolved (test using limewater)

how to test for chloride ions using nitric acid, and then silver nitrate solution

Cl^- + HNO₃

Cl^- + AgNO₃

add nitric acid to remove any impurities

add silver nitrate, if chloride ions are present they will produce a white precipitate

how to test for bromide ions using nitric acid, and then silver nitrate solution

Br^- + HNO₃

Br^- + AgNO₃

add nitric acid to remove any impurities

add silver nitrate, if bromide ions are present they will produce a cream precipitate

how to test for iodide ions using nitric acid, and then silver nitrate solution

I^- + HNO₃

I^- + AgNO₃

add nitric acid to remove any impurities

add silver nitrate, if iodide ions are present they will produce a yellow precipitate