Qualitative Analysis [3]

Question 1

Test for halides?

Answer 1

The silver nitrate test. Add AgNO₃ and a precipitate will form.

A white precipitate is AgCl
A cream precipitate is AgBr
A yellow precipitate is AgI

Question 2

Confirmation test for halides?

Answer 2

Add to ammonia solution

AgCl dissolves in dilute ammonia solution
AgBr only dissolves in concentrated ammonia solution
AgI is not soluble in ammonia

Question 3

Test for carbonates?

Answer 3

Add sulphuric acid. The carbonate reacts with the H⁺ ions, creating CO₂. The carbon dioxide can be seen as effervescence.

CO₃²⁻ + 2H⁺ ➞ CO₂ + H₂O

Question 4

Test for sulphates?

Answer 4

Add a nitric acid (Anything but sulphuiric acid) to remove carbonate ions (Barium carbonate is a white precipitate).

Add Barium nitrate. A white precipitate is Barium Sulphate

Question 5

Test for ammonium?

Answer 5

Gently heat ammonium with hydroxide solution. The solution will reach alkaline ammonia gas, which will turn damp red litmus paper blue.