Tests for Anion and Gases

Question 1

Nitrate ions (NO3)-

Answer 1

Addition of Aqueous NaOH, followed by aluminium metal.
Warm Gently, ammonia gas is evolved that turns damp red litmus paper blue.

Question 2

Carbonate ions, (CO3)2-

Answer 2

Addition of any acid, Carbon Dioxide gas is released.
Test using limewater or extinguishing of lighted splint.

Question 3

Chlorine Ions (Cl)-

Answer 3

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of silver nitrate, white ppt(Silver Chloride) formed.

Question 4

Iodide Ions I-

Answer 4

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of silver nitrate, yellow ppt(Silver Iodide) formed.

Question 5

Sulfate ions (SO4)2-

Answer 5

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of barium nitrate, white ppt, Barium Sulfate, formed

Question 6

Ammonia gas

Answer 6

damp red litmus paper turns blue

Question 7

Carbon Dioxide

Answer 7

forms a white ppt when bubbled through limewater, ppt dissolves in excess CO2

Question 8

Chlorine Gas

Answer 8

Red Litmus paper turns blue then is bleached.
Blue litmus paper is bleached.

Question 9

Hydrogen Gas

Answer 9

extinguishes a lit splint with a pop

Question 10

Oxygen gas

Answer 10

Glowing splint relights

Question 11

Sulfur dioxide gas

Answer 11

Acidified potassium manganate (VII) turns from purple to colourless

Question 12

Addition of Aqueous NaOH, followed by aluminium metal.
Warm Gently, ammonia gas is evolved that turns damp red litmus paper blue.

Answer 12

Nitrate ions (NO3)-

Question 13

Addition of any acid, Carbon Dioxide gas is released.
Test using limewater or extinguishing of lighted splint.

Answer 13

Carbonate ions, (CO3)2-

Question 14

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of silver nitrate, white ppt formed.

Answer 14

Chlorine Ions (Cl)-

Question 15

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of silver nitrate, yellow ppt formed.

Answer 15

Iodide Ions I-

Question 16

Addition of dilute nitric acid to remove interfering hydroxide and carbonate ions to prevent a false positive.

Addition of barium nitrate, white ppt, formed

Answer 16

Sulfate ions (SO4)2-

Question 17

damp red litmus paper turns blue

Answer 17

Ammonia gas

Question 18

forms a white ppt when bubbled through limewater, ppt dissolves in excess CO2

Answer 18

Carbon Dioxide

Question 19

Red Litmus paper turns blue then is bleached.
Blue litmus paper is bleached.

Answer 19

Chlorine Gas

Question 20

extinguishes a lit splint with a pop

Answer 20

Hydrogen Gas

Question 21

Glowing splint relights

Answer 21

Oxygen gas

Question 22

Acidified potassium manganate (VII) turns from purple to colourless

Answer 22

Sulfur dioxide gas