The reaction of chlorine gas with concentrated aqueous sodium hydroxide at elevated…
CHEMISTRY · Multi-part · A Level · Chemistry · Oxidation, reduction and redox reactions · Oxidation, reduction and redox reactions
Problem
The reaction of chlorine gas with concentrated aqueous sodium hydroxide at elevated temperature produces both chloride and chlorate ions according to the balanced equation below.
3Cl2(g)+6OH−(aq)→5Cl−(aq)+ClO3−(aq)+3H2O(l)
This process is an example of a disproportionation reaction, in which the same element is simultaneously oxidized and reduced.
(1) Assign oxidation numbers to chlorine in each of the three chlorine-containing species that appear in the equation above.
(2) Identify the chlorine-containing species that is oxidized and the one that is reduced.
(3) Explain, in terms of oxidation-number changes, why this reaction qualifies as a disproportionation reaction.