Uses of chlorine and chlorate (I)

Question 1

What does chlorine form with water?

Answer 1

Hydrochloric acid and chloric(I) acid

Question 2

What is the equation for the reaction of chlorine and water?

Answer 2

Cl2(aq) + H2O(l) ⇌ HCl(aq) + HClO (aq)
Disproportionation reaction as chlorine becomes +1 and -1

Question 3

What does chloric(I) acid (HClO) dissociate into?

Answer 3

• H+ and ClO-
• ClO- is an oxidising agent, so toxic.
• At low conc. toxic effects are harmless to humans, but kill any bacteria

Question 4

What are the benefits of chlorination?

Answer 4

Kills bacteria, preventing disease

Question 5

What are the two downsides to chlorination?

Answer 5

• Toxic effects could harm humans at high conc.
• Wasteful to chlorinate whole water supply when so little used to drink/cook

Question 6

How does chlorine react with water in sunlight?

Answer 6

2Cl2(aq) + 2H2O(l) -> 4HCl(aq) + O2(aq)

Doesn’t produce HClO so pools need topping up with chlorine to keep killing bacteria

Question 7

What does chlorine react with to form sodium chlorate (I) (oxidising agent in bleach)?

Answer 7

Cold, dilute sodium hydroxide

Question 8

What is the equation for the reaction of chlorine with cold, dilute sodium hydroxide?

Answer 8

Cl2(aq) + 2NaOH(aq) –> NaClO(aq) + NaCl(aq) + H2O(l)

Disproportionation reaction