F.5 Chemistry Question 4

Question

Briefl discribe how to define redox reaction and non-redox reactions. You should use the following reactions as example.
Reaction 1：Na2CO3¯ + 2 HCl → 2 NaCl + CO2 + H2O
Reaction 2：MnO4¯ + 8 H+ + 5 Fe2+ → Mn2+ + 4 H2O + 5 Fe3+

Answer 1

Reaction 1：Na2CO3¯ + 2 HCl → 2 NaCl + CO2 + H2O
There are no oxidation number change for any element in the reaction. It is not a redox reaction.
Reaction 2：MnO4¯ + 8 H+ + 5 Fe2+ → Mn2+ + 4 H2O + 5 Fe3+
Mn has oxidation number change from +7 to +2, it is reduced in the raction.
Fe has oxidation number changed from +2 to +3, it is oxidzed in the reaction.
As there is oxidation numbers changed in the reaction, it is a redox reaction.