Test for cations

Question 1

What do flame tests identify ?

Answer 1

Metal ions

Question 2

How do you test for metal ions using a flame test ?

Answer 2

Compounds of some metals burn with a characteristic colour, so you can test for various metal ions by heating your substance and seeing whether it burns with a distinctive colour flame.

Question 3

What metal ions burns with a crimson flame ?

Answer 3

Lithium ions.

Li+

Question 4

What metal ions burn with a yellow flame ?

Answer 4

Sodium ions

Na+

Question 5

What metal ions burn with a lilac flame ?

Answer 5

Potassium

K+

Question 6

What metal ions burn with an orange-red flame ?

Answer 6

Calcium ions

Ca2+

Question 7

What metal ions burn with a green flame ?

Answer 7

Copper ions

Cu2+

Question 8

How do u do the flame test ?

Answer 8

To do the test, you first need to clean a platinum wire loop by dipping it in some dilute HCL and then holding it in a blue flame from a Bunsen burner until it burns without any colour. Then, dip the
loop into the sample you want to test and put it back in the flame. Record the colour of the flame.

You can use these colours to detect and identify different ions. However it only works for samples that contain a single metal ions. If the sample tested contains a mixture of metal ions, the flame colours of some ions may be hidden by the colours of others.