Cation Tests Flashcards
1
Q
what type of ions are cations?
A
positive ions e.g. Na+
2
Q
how do you conduct a flame test?
A
- dip a piece of nichrome/platinum wire into hydrochloric acid - these wires don’t colour the flame, and the acid cleans the wire
- dip the wire into a sample of solid or solution - this causes some of the sample to stick onto the wire
- place the tip of the wire into a non-luminous Bunsen flame
3
Q
what colour flame does Li+ have?
A
red
4
Q
what colour flame does Na+ have?
A
yellow
5
Q
what colour flame does K+ have?
A
lilac
6
Q
what colour flame does Ca2+ have?
A
orange-red
7
Q
what colour flame does Cu2+ have?
A
blue-green
8
Q
what do we use to test for ammonium ions?
A
sodium hydroxide
9
Q
how to conduct an ammonium test?
A
- dissolve the sample in water
- add some NaOH (aq) and warm it
- test the gas evolved with damp red litmus paper
10
Q
if ammonium ions are present in the test sample, what colour will the litmus paper turn?
A
blue
