Test for ammonium ions Flashcards
1
Q
What is this testing for?
A
Compounds containing ammonium ions NH₄⁺
2
Q
Step 1
A
Add sodium hydroxide to sample and gently heat
3
Q
Why add sodium hydroxide?
A
Ammonium ion reacts with OH ion:
NH₄⁺ + OH⁻ ——> NH₃ + H2O
So ammonia gas is produced
4
Q
How to test for ammonia gas?
A
Hold damp litmus paper near tube
Gas dissolves in water to form alkaline solution
5
Q
Colour change on litmus paper
A
Red to blue
6
Q
What must the litmus paper be?
A
Damp so gas can dissolve in water on litmus paper
