During municipal water treatment and in outdoor swimming pools, chlorine is added to sanitise water. However, in the presence of sunlight (UV radiation), chlorine undergoes a rapid photochemical reaction with water rather than forming the weak acid responsible for disinfection.
Which equation correctly represents this decomposition reaction of chlorine in water in the presence of sunlight?
Cl2(aq)+H2O(l)⇌HClO(aq)+HCl(aq)Cl_2(aq) + H_2O(l) \rightleftharpoons HClO(aq) + HCl(aq)Cl2(aq)+H2O(l)⇌HClO(aq)+HCl(aq)
2Cl2(aq)+H2O(l)→2HCl(aq)+Cl2O(aq)2Cl_2(aq) + H_2O(l) \rightarrow 2HCl(aq) + Cl_2O(aq)2Cl2(aq)+H2O(l)→2HCl(aq)+Cl2O(aq)
2Cl2(aq)+2H2O(l)→4HCl(aq)+O2(g)2Cl_2(aq) + 2H_2O(l) \rightarrow 4HCl(aq) + O_2(g)2Cl2(aq)+2H2O(l)→4HCl(aq)+O2(g)
Cl2(aq)+H2O(l)→2HCl(aq)+O(g)Cl_2(aq) + H_2O(l) \rightarrow 2HCl(aq) + O(g)Cl2(aq)+H2O(l)→2HCl(aq)+O(g)
32 exam-style questions on OCR GCSE Chemistry Interpreting and interacting with earth systems. Each one has a worked solution and a mark scheme showing where the marks go.