Anions and Cation plus gases in the Atmopshere

Question 1

What are the three anions you can test for?

Answer 1

Carbonates, Sulfates and Halide Anions

Question 2

Test For Carbonates?

Answer 2

Add Hcl (Or any acid) to Carbonates

2Hcl + CO3 –> CO2 + H2O

Use CO2 test (turns limewater cloudy)

Question 3

Test for Sulfates?

Answer 3

Add dilute Hydrochloric acid into sulfate solution

XSO4 + BaCl2 –> BaSO4

Barium Sulfate forms a white Precipitate

Question 4

Test for Halide Anions?

Answer 4

Add Nitric Acid and Silver Nitrate
AgNO3 -Silver Nitrate

NO3- will disperse

Ag+ + Cl- –> AgCl (White Precipitate)

Ag+ + Br- –> AgBr (Creamy Precipitate)

Ag+ + I- –> AgI (Yellow Precipitate

Question 5

What are the three Cations tests that you can test for?

Answer 5

Flame Tests
Ammonium Ions
CU2+ Fe2+ Fe3+

Question 6

What flames are given for each postive metal ion in a flame test?

Answer 6

Li --> Red Flame
Na --> Yellow Flame
K --> Lilac Flame
Calcium --> Orange/Red Flame
Copper --> Blue-Green Flame

Question 7

What are the Tests for Cu2+, Fe2+ and Fe3+ ?

Answer 7

Add Sodium Hydroxide

Copper (II) –> Blue Precipitate
Cu2+ + 2OH- –> Cu(OH)2

Iron (II) –> Green Precipitate
Fe2+ + 2OH- –> Fe(OH)2

Iron (III) –> Brown Precipitate
Fe2+ + 3OH- –> Fe(OH)3

Question 8

Why does the test for Cu2+, Fe2+ and Fe3+ Work?

Answer 8

Because they are insoluble, they will form out of the solution to produce crystals (colours of crystals will differ)

Question 9

Test for Ammonium Ions?

Answer 9

React Ammonium Ion with NaOH

Produce Ammonia Gas

Since Ammonia is a Base

Litmus Paper = Blue

NH4+ + OH- –> NH3 + H2O