Halides as reducing agents

Question 1

The reducing power of the halides _____ down the group

Answer 1

Increases

Question 2

Give the equation of solid sodium chloride and concentrated sulfuric acid

Answer 2

Cl⁻ + H₂SO₄ → HCl + HSO₄⁻

Question 3

Give the change in oxidation state for S in the reaction of solid sodium chloride and concentrated sulfuric acid

Answer 3

0 (There is no change, Cl⁻ does not reduce)

Question 4

Give the observations of the reaction of solid sodium chloride and concentrated sulfuric acid

Answer 4

White steamy fumes (due to HCl)

Question 5

Give the equation for the reaction of solid sodium bromide and concentrated sulfuric acid

Answer 5

2Br⁻ + H₂SO₄ + 2H⁺ → Br₂ + SO₂ + 2H₂O

Question 6

Give the change in oxidation state of S for the reaction of solid sodium bromide and sulfuric acid

Answer 6

-2

Question 7

Give the observations of the reaction of solid sodium bromide and concentrated sulfuric acid

Answer 7

Orange vapour (due to Br₂)
Choking gas (due to SO₂)

Question 8

Give the equations for the reaction of solid sodium iodide and concentrated sulfuric acid

Answer 8

6I⁻ + H₂SO₄ + 6H⁺ → 3I₂ + S + 4H₂O

8I⁻ + H₂SO₄ + 8H⁺ → 4I₂ +H₂S + 4H₂O

Question 9

Give the changes in oxidation state for S in the reaction of solid sodium iodide and concentrated sulfuric acid

Answer 9

-6 (S)

-8 (H₂S)

Question 10

Give the observations for the reaction of solid sodium iodide and concentrated sulfuric acid

Answer 10

Purple vapour (due to I₂)
Yellow solid (due to S)

Purple vapour (due to I₂)
Foul smelling gas (due to H₂S)