reactions of chlorine and water

use for chlorine gas

sterilising water

how does chlorine sterilise water?

it is a poisinous gas soluble in water which kills bacteria

equation for the reaction of chlorine in water?

Cl2(g) + H2O(l) →<_ HCl + HClO

colour of the equilibrium solution?

green

why is the equilibrium solution green?

chlorine gas is present

what type of reaction is this?

disproportionation

why is this a disproportionation reaction?

Cl is oxidised 0→ +1 in HClO and reduced 0 → -1 in HCl

what happens in the presence of sunlight?

the green colour fades and a colourless gas is produced

equation for the reaction in sunlight

2Cl2(g) + 2H2O(l) → 4HCl (aq)+ O2(g)

which is the reducing agent?

oxygen- its oxidised -2→0

which is the oxidising agent?

chlorine- its reduced 0→-1

equation for the reaction of chlorine with dilute sodium hydroxide

Cl2(g) + 2NaOH(aq) → NaCl(aq) + NaClO(aq) + H2O(l)

why is the equilibrium destroyed when water is replaced with sodium hydroxide?

the NaOH reacts with the acids formed

what is this reaction used for?

commercial production of bleach

what happens if the reaction between chlorine and NaOH is heated to 70C?

the rate of reaction speeds up