Testing for Ions

Question 1

Test for CO₃²⁻ and equation

Answer 1

Add nitric acid, effervescence will occur
Bubble gas through limewater and if positive it will turn limewater cloudy
CO₃²⁻ + 2H⁺ → CO₂ + H₂O

Question 2

Test for SO₄²⁻ and equation

Answer 2

Add BaCl₂, white precipitate of barium sulphate forms
Ba²⁺ + SO₄²⁻ → BaSO₄

Question 3

Test for Fe²⁺ and equation

Answer 3

Add NaOH, and a green precipitate forms
Fe²⁺ + 2OH⁻ → Fe(OH)₂

Question 4

Test for NH₄⁺ and equation

Answer 4

Add NaOH and heat gently. The gas formed will turn damp red litmus paper blue
NH₄⁺ + OH⁻ → NH₃ + H₂O