Qualitative Analysis

Question 1

What order to test in

Answer 1

1) carbonate co32- to see if co2 produced

2) sulfate to see if so42- ions proceed

3) halide ions

Question 2

Carbonate ions test + ionic equation

Answer 2

• add HCL to solution if bubbles test to see if co2 produced

• bubble through limewater turns milky

Co32- + 2H+&raquo_space;> co2 + h2o

Question 3

Sulfate ions test + ionic question

Answer 3

(Add hcl to remove carbonate)

• add barium chloride solution if white precipitate formed then so42- ions present

Ba2+ + so42-&raquo_space; baso4

Question 4

Halide ions test and ionic equations

Answer 4

• add silver to them

• dissolve halide in water
- add silver nitrate + record colour of precipitate if colour too hard to see

Further: add ammonia nh3

• cl- = white precipitate + dissolves in dilute ammonia
  Ag+ + cl-&raquo_space; AgCl
• br- = cream precipitate + dissolves in conc ammonia
  Ag+ + Br-&raquo_space; AgBr
• I- = yellow precipitate + insoluble in conc ammonia

I- + Ag&raquo_space; AgI

Question 5

Test for ammonium + ionic equation

Answer 5

• add NaOH (sodium hydroxide) to solution should and HEAT gently
• produces ammonia gas NH3

• damp litmus paper turns from red to blue if present as NH4+ dissolves in water

NH4+ + OH-&raquo_space; NH3 + H20