Qualitative analysis

what is the test for carbonate ions?

add a dilute acid

if carbonates are present what gas will be released?

carbon dioxide will be released

what is the test for carbon dioxide?

limewater

what colour does carbon dioxide turn limewater?

carbon dioxide turns limewater cloudy

what is the test for sulfate ions?

add dilute hydrochloric acid followed by barium chloride solution

how to test for halide ions?

add nitric acid then silver nitrate solution

what colour precipitate is silver chloride?

a white precipitate

what colour precipitate is silver bromide?

a cream precipitate

what colour precipitate is silver iodide?

a yellow precipitate

what substance can you use to tell the silver halides apart?

test the solubility in ammonia

which silver halide dissolves in dilute NH3 and concentrated NH3?

silver chloride

which silver halide doesn’t dissolve in dilute NH3 but dissolves in concentrated NH3?

silver bromide

which silver halide doesn’t dissolve in dilute NH3 or in concentrated NH3?

silver iodide

what can you use to check for ammonia gas?

a damp piece of red litmus paper

if ammonia is present what colour will the litmus paper turn?

blue

what is the test for ammonium ions, NH4+?

• add some sodium hydroxide to the mystery substance in the test tube and warm the mixture

to avoid mix ups what way should tests be done?

• test for carbonates

• test for sulphates

• test for halides