About Halogens - Group 7/17

Question 1

Reactions w/ Hydrogen

Answer 1

Cl - Explodes in sunlight + reacts slowly in the dark

Br - Reacts slowly in heat w/ platinum catalyst

I - reacts partially + slowly

Question 2

Reactions w/ Iron Wool (Metal)

Answer 2

Cl - Iron wool burns + glows brightly

Br - Iron wool glows but less brightly than w/ Cl

I - Iron wool has a very slight glow (reversible reaction)

Question 3

Uses of Chlorine

Answer 3

• Soluble in water: used to treat drinking water + swimming pools

Cl2 (g) + H2O => HCl (aq) + HClO (aq)
- Chloric (I) acid used to purify water by killing pathogens through oxidation

• Example of disproportionation - stimultaneous oxidation + reduction of a species