Test For Ions/Atoms Flashcards
Lithium in the flame test.
Crimson
Sodium.
Yellow/orange.
Potassium
Lilac (pink through cobalt glass)
Calcium
Brick red
Barium
Apple green
Copper
Green-blue
What is the test for ammonium?
Warm with a solution of sodium hydroxide. A pungent smell will be observed.
This is due to the ammonium reacting with the OH ions, water and ammonia is formed.
What is the test for sulphate ions?
Make a solution and add a solution of barium chloride or barium nitrate, a white precipitate will be formed.
How do you perform the test for halide ions?
Make a solution in dilute nitric acid and add silver nitrate solution.
Chloride.
White precipitate, soluble in dilute ammonia solution.
Bromide
Cream precipitate, soluble in concentrated ammonia solution.
Iodide.
Yellow precipitate, insoluble in concentrated concentrated ammonia solution.
What is the test for carbonate ions?
Add dilute acid to form colourless gas which turns limewater milky.
What is the test for iodine?
Add a few drops of starch solution, the solution will turn blue-black.
Hydrogen.
Gives a pop with a burning splint.
Oxygen
Relight a glowing splint.
Chlorine
Bleaches damp litmus/Universal indicator.
Carbon dioxide.
Bubble through limewater, limewater turns milky.
Hydrochloric acid.
White fumes produced when a glass rod is dipped in concentrated ammonia.
Ammonia.
White fumes produced when glass rod is dipped in concentrated hydrochloric acid
What molecule is present if there is a colourless liquid with alcohol smell?
Possibly an alcohol
What is produced when a colourless liquid with a sharp irritating smell is produced?
Possibly a carboxylic acid
How do you test for carbon content?
Place a few drops of the liquid on a watch glass and light with a splint.
What is produced in a low carbon content (alcohol)?
Non sooty/clean blue flame.
What is produced in a high carbon content?
Sooty yellow/orange flame.
How do you test for an alcohol group?
Phosphorus pentachloride.
How do you carry out the test to determine the alcohol group?
Add a few crystals of PCl5 to a few cm3 of the liquid. Test any gas released with a glass rod dipped in concentrated ammonia solution.
What is produced if an alcohol is present?
Misty fumes, solid disappears, white smoke (ammonium chloride).
What is observed if an alcohol isn’t present?
No gas released, no white smoke with conc. ammonia solution.
How do you test for a primary/secondary alcohol as opposed to a tertiary?
Mix a few cm3 of the liquid or solution with acidified potassium dichromate solution in a test tube and warm in a water bath.
What is observed if a primary alcohol is present?
Orange solution changes to green, change in smell.
What is observed if a primary alcohol is not present?
Solution remains orange.
