Anion Testing

Question 1

How can chloride (Cl-) ions be identified?

Answer 1

1. Red litmus stays red
2. Add silver nitrate and dilute nitric acid: precipitate
3. Add dilute ammonia: precipitate dissolves

Question 2

How can bromide (Br-) ions be identified?

Answer 2

1. Red litmus stays red
2. Add silver nitrate and dilute nitric acid: precipitate
3. Add dilute ammonia: no change
4. Add concentrated ammonia: precipitate dissolves

Question 3

How can iodide (I-) ions be identified?

Answer 3

1. Red litmus stays red
2. Add silver nitrate and dilute nitric acid: precipitate
3. Add dilute ammonia: no change
4. Add concentrated ammonia: no change

Question 4

How can hydroxide (OH-) ions be identified?

Answer 4

1. Red litmus turns blue
2. Add dilute nitric acid: no bubbles
3. Add copper nitrate: blue precipitate

Question 5

How can acetate (CH3COO-) ions be identified?

Answer 5

1. Red litmus turns blue
2. Add dilute nitric acid: no bubbles
3. Add copper nitrate: no precipitate

Question 6

How can carbonate (CO3 2-) ions be identified?

Answer 6

1. Red litmus turns blue
2. Add dilute nitric acid: bubbles

Question 7

How can sulfate (SO4 2-) ions be identified?

Answer 7

1. Red litmus stays red
2. Add silver nitrate and dilute nitric acid: no precipitate
3. Fresh sample, add dilute nitric acid and barium nitrate: precipitate

Question 8

How can phosphate (PO4 3-) ions be identified?

Answer 8

1. Red litmus stays red
2. Add silver nitrate and dilute nitric acid: no precipitate
3. Fresh sample, add dilute nitric acid and barium nitrate: no precipitate
4. Fresh sample. add ammonia and barium nitrate: precipitate