Test for Anions and Cations Flashcards
What is the test for carbonate
add dilute acid
test gas released
gas produced should be carbon dioxide which will form a white precipitate of calcium carbonate when bubbled through limewater
What is the test for sulfate ions
add HCL to sample and add barium chloride if present white precipitate of barium sulfate should form
Why should u add HCL in sulfate test
because it prevents precipitation reactions
what is the test for Halide ions
add nitric acid and silver nitrate
if chloride present - white precipitate
if bromide present - cream precipitate
if iodide present - yellow precipitate
why should u add nitric acid to halide ion test
because it gets rid of carbonate ions that could produce precipitates that confuse results
why cant u add HCL to halide ion test instead
because you would be adding chloride ions
what is the test for a metal ion
precipitation reaction:
add sodium hydroxide if hydroxide precipitate forms use colour to identify the metal
Aluminium - White , colourless when reacted with excess NaOH
Calcium - White
Copper - Blue
Iron II - Green
Iron III - Brown
how can we differ Calcium and Aluminium
calcium doesn’t dissolve in NaOH but aluminium does
why shouldn’t you add sodium hydroxide quickly
because the precipitation dissolves
What is the test for ammonium
add sodium hydroxide to solution and if ammonium ion present , ammonium gas should be present by adding NaOH and gently heating and red litmus paper should turn blue
