Tests For Ions And Gases COPY Flashcards
Sodium flame
Orange
Potassium flame
Lilac
Calcium flame
Brick red
Testing for ammonia NH4+
Warm with sodium hydroxide solution. Damp with red litmus. Result - litmus paper turns blue, pungent smelling gas
What do you use for precipitation tests with copper, iron fe2+ and fe3+
Sodium hydroxide
Colour of copper precipitate
Blue
Colour of iron fe2+ precipitate
Green
Colour of iron fe3+ precipitate
Brown
What do you use for precipitation tests with chlorine, bromine and iodine
Dilute nitric acid and silver nitrate solution
Colour of chlorine precipitate
White
Colour of bromine precipitate
Cream
Colour of iodine precipitate
Yellow
Test for sulphate SO4 2-
Use dilute hydrochloride acid and barium chloride solution. Positive result : White precipitate
Test for carbonate CO3 2-
Using dilute hydrochloric acid. Bubble it through limewater. Positive result : limewater turns cloudy
Test for oxygen gas
Put a glowing splint into the gas. Splint should relight
Test for carbon dioxide
A lighted wooden splint goes out in a test tube of carbon dioxide but this happens with other gases, too. It is better to bubble the test gas through lime water (calcium hydroxide solution) . Carbon dioxide turns limewater cloudy white
Test for ammonia
Ammonia had a characteristic sharp, choking smell. It also makes damp red litmus paper turn blue. Ammonia forms a white smoke of ammonium chloride when hydrogen chloride gas, from concentrated hydrochloric acid, is held near it
Test for chlorine
Chlorine has a characteristic shark, choking smell. It also makes damp blue litmus paper turn red, and then bleaches it white. Chlorine makes damp starch - iodide paper turn blue black
Lithium flame
Red
Test for hydrogen
Put a lit splint into the gas Hydrogen burns with a ‘squeaky pop’ sound
