Identification of IONS and GASES

Question 1

Add aq. NaOH (sodium hydroxide) to Aluminium

Answer 1

⚪ WHITE Ppt is formed
— soluble (dissolves) in excess NaOH

Question 2

Add aq. NH₃ (ammonia) to Aluminium

Answer 2

⚪ WHITE Ppt is formed
INSOLUBLE in excess

Question 3

Add aq. NaOH (sodium hydroxide) to Ammonium (NH₄)

Answer 3

NO ppt.
Heating releases ammonia (NH₃ gas)

Question 4

Add aq. NH₃ (ammonia) to Ammonium

Answer 4

NO ppt.
Heating releases ammonia (NH₃) gas

Question 5

Add aq. NaOH (sodium hydroxide) to Calcium

Answer 5

⚪ WHITE Ppt is formed
INSOLUBLE in excess

Question 6

Add aq. NH₃ (ammonia) to Calcium

Answer 6

NO ppt.

Question 7

Add aq. NaOH (sodium hydroxide) to Chromium (3+)

Answer 7

🟢 GREEN ppt is formed
SOLUBLE (dissolves) in excess
^ forms a green solution

Question 8

Add aq. NH₃ (ammonia) to Chromium (3+)

Answer 8

🟢⚪Grey-Green ppt is formed
INSOLUBLE in excess

Question 9

Add aq. NaOH (sodium hydroxide) to Copper (2+)

Answer 9

🔵Light blue ppt is formed
INSOLUBLE in excess

Question 10

Add aq. NH₃ (ammonia) to Copper (2+)

Answer 10

🔵Light blue ppt is formed
SOLUBLE (dissolves) in excess
^ gives a deep blue solution

Question 11

Add aq. NaOH (sodium hydroxide) to Iron (2+)

Answer 11

🟢GREEN ppt is formed
INSOLUBLE in excess

Question 12

Add aq. NH₃ (ammonia) to Iron (2+)

Answer 12

🟢 GREEN ppt is formed
INSOLUBLE in excess

Question 13

Add aq. NaOH (sodium hydroxide) to Iron (3+)

Answer 13

🔴Red-brown ppt formed
INSOLUBLE in excess

Question 14

Add aq. NH₃ (ammonia) to Iron (3+)

Answer 14

🔴Red-Brown ppt is formed
INSOLUBLE in excess

Question 15

Add aq. NaOH (sodium hydroxide) to Zinc (2+)

Answer 15

⚪WHITE ppt is formed
SOLUBLE in excess
^gives colourless solution

Question 16

Add aq. NH₃ (ammonia) to Zinc (2+)

Answer 16

⚪WHITE ppt is formed
SOLUBLE in excess
^ gives colourless solution

Question 17

What color flame is produced by Lithium (Li⁺)?

Answer 17

🔴 Crimson-red flame

Question 18

What color flame is produced by Sodium (Na⁺)?

Answer 18

🟡Yellow flame

Question 19

What color flame is produced by Potassium (K⁺)?

Answer 19

🟣Lilac flame

Question 20

What color flame is produced by Calcium (Ca²⁺)?

Answer 20

🟠Orange-red flame

Question 21

What color flame is produced by Barium (Ba²⁺)?

Answer 21

🟢Apple-green flame

Question 22

What color flame is produced by Copper(II) (Cu²⁺)?

Answer 22

🔵🟢Blue-green flame

Question 23

What is the test for Ammonia (NH₃)?

Answer 23

Test with damp red litmus paper; it turns blue.

Question 24

How can you identify Carbon Dioxide (CO₂)?

Answer 24

Bubble through limewater; a white precipitate of calcium carbonate forms, turning limewater milky.

Question 25

What happens when Chlorine (Cl₂) is tested with damp litmus paper?

Answer 25

It is bleached.

Question 26

What is the result of testing Hydrogen (H₂) with a lighted splint?

Answer 26

A squeaky pop sound is heard.

Question 27

How is Oxygen (O₂) identified?

Answer 27

Test with a glowing splint; it relights.

Question 28

What is the test for Sulfur Dioxide (SO₂)?

Answer 28

Test with acidified potassium manganate(VII); the solution changes from purple to colorless.

Question 29

Everything made if copper (ppt, oxides, etc) are blue. EXCEPT...

Answer 29

Copper Chloride (CuCl₂) and copper carbonate (CuCO₃)