Test for ammonium ions

Question 1

What is this testing for?

Answer 1

Compounds containing ammonium ions NH₄⁺

Question 2

Step 1

Answer 2

Add sodium hydroxide to sample and gently heat

Question 3

Why add sodium hydroxide?

Answer 3

Ammonium ion reacts with OH ion:
NH₄⁺ + OH⁻ ——> NH₃ + H2O
So ammonia gas is produced

Question 4

How to test for ammonia gas?

Answer 4

Hold damp litmus paper near tube
Gas dissolves in water to form alkaline solution

Question 5

Colour change on litmus paper

Answer 5

Red to blue

Question 6

What must the litmus paper be?

Answer 6

Damp so gas can dissolve in water on litmus paper