A student had three different solutions in beakers 1, 2 & 3 as shown in Figure 1.
Figure 1
The beakers contained one of the following solutions but the student did not know which beaker contained each solution.
- potassium bromide
- calcium sulfate
- copper nitrate
To identify the solutions, the student performed a flame test.
Describe how to carry out a flame test.
The student recorded the flame colour that was observed with the solutions in beakers 1, 2 and 3.
Draw one line from each solution to the colour of the flame that it would produce.
The student wanted to confirm the identity of the solutions in beakers 1, 2 and 3 so performed further tests on the solutions.
They added dilute nitric acid followed by barium nitrate solution to each of the solutions.
Which of the solutions would produce a white precipitate?
Tick (✓) one box.
Potassium bromide | |
Calcium sulfate | |
Copper nitrate |
The student added dilute nitric acid and silver nitrate solution to each of the solutions.
Which solution would produce a cream precipitate?
Tick (✓) one box.
Potassium bromide | |
Calcium sulfate | |
Copper nitrate |
Finally, the student added a few drops of sodium hydroxide solution to each of the solutions.
Which solution would form a white precipitate?
Tick (✓) one box.
Potassium bromide | |
Calcium sulfate | |
Copper nitrate |
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