Qualitative Analysis Flashcards
How would you carry out a flame test?
Clean a nichrome wire loop by dipping it into hydrochloric acid then rinsing it in distilled water. Dip the wire into a sample of the compound and put the loop into a clear blue Bunsen flame. Record the colour
What colour does lithium turn in a flame test?
Crimson red
What colour does sodium turn in a flame test?
Yellow
What colour does potassium turn in a flame test?
Lilac
What colour does calcium turn in a flame test?
Orange red
What colour does copper turn in a flame test?
Blue green
How would you carry out a sodium hydroxide test?
Add a few drops of sodium hydroxide solution to a solution of the compound. If a hydroxide precipitate forms, you can use the colour to determine the metal ion in the compound
What colour does aluminium make in a sodium hydroxide test?
White at first, but then redissolved in excess sodium hydroxide to form a colourless solution
What colour does calcium make in a sodium hydroxide test?
White
What colour does copper make in a sodium hydroxide test?
Blue
What colour does iron(II) make in a sodium hydroxide test?
Green
What colour does iron(III) make in a sodium hydroxide test?
Brown
What do ammonium ions produce in sodium hydroxide solution?
When you gently heat it it gives off ammonia gas. You can test for this by holding a piece of damp red litmus paper over it. Ammonia gas will turn it blue.
How do you test for halide ions?
Add some dilute nitric acid followed by a few drops of silver nitrate solution. Chloride, bromide, and iodide ions all give different colour precipitates
What colour precipitate does chloride form in silver nitrate solution?
White