Test For Cations Flashcards
Learn about the respective tests for each cation.
What is the chemical equation for the reaction that occurs when testing for ammonium ions?
NH4+(aq) + OH-(aq)»_space;> NH3 (g) + H20(l)
What is the first step in the test of ammonium ions?
Aqueous NaOH is added to ammonium ion solution.
What is second step in the test for ammonium ions?
Ammonia gas produced.
What is the third step in the test for ammonium ions?
Warm the mixture, to allow the release of the ammonia gas.
What is the final step in the test for ammonium ions?
Use moist pH indicator paper, and as ammonia is alkali, it’s presence will turn the paper blue.
What is the chemical equation for the reaction that occurs when testing for carbonate ions?
Na2CO3(aq) + 2HNO3(aq)»_space;> 2NaNO3(aq) + CO2(g) +
H20(l)
What is step one in the test for carbonate ions?
In a test tube, add dilute HNO3 to the solid or solution to be tested.
What is step two in the test for carbonate ions?
If you see bubbles, the unknown compound could be a carbonate.
What is step three in the test for carbonate ions?
To prove that the gas produced is CO2:
- bubble gas through limewater (saturated aqueous solution of calcium hydroxide Ca(OH)2
- white precipitate formed, turns lime water cloudy
What is the chemical equation for the reaction between CO2 and limewater?
CO2(g) + Ca(OH)2(aq)»_space;> CaCO3(s) +H2O(l)
What sulfate compound is very insoluble?
Barium Sulfate (BaSO4)
What is the ionic equation between Ba2+ ions and a solution of SO4(2-)?
Ba2+(aq) + SO4(2-)(aq)»_space;> BaSO4(s)
What is the chemical equation for the reaction between silver and any halide ion?
Ag+(aq) + X-(aq)»_space;> AgX(s)
What is step one in the test for halide ions?
Add aqueous silver nitrate AgNO3 to an aqueous solution of a halide.
What is step two of the test for halide ions ?
Identifying the formed precipitates colour:
Silver Chloride - White
Silver Bromide - Cream
Silver Iodide - Yellow
