Which change requires an oxidising agent?
1- 2S2O3 ---------- S4O6(2-)
2-Zn2+ -------------- Zn
3- ClO- --------- Cl-
4- SO3 -------- SO4(2-)
how to know?
The answer should be option 4.
Oxidising agent is a substance which oxidises other substance and itself gets reduced. Thus in the given changes, we need to find out in which change, oxidation is taking place, i.e. either there should be an increase in oxidation state or addition of oxygen.
In option 1, there is addition of electron. So there is reduction.
In option 2, Zn2+ is getting reduced to Zn by gaining 2 electrons.
In option 3, oxidation state of Cl on LHS is +1 while on RHS is -1. Thus oxidation state is decreasing. So it is reduction.
In option 4, oxidation state of S on both sides is +6, but there is addition of oxygen. So there is oxidation.
Oxidising agent is a substance which oxidises other substance and itself gets reduced. Thus in the given changes, we need to find out in which change, oxidation is taking place, i.e. either there should be an increase in oxidation state or addition of oxygen.
In option 1, there is addition of electron. So there is reduction.
In option 2, Zn2+ is getting reduced to Zn by gaining 2 electrons.
In option 3, oxidation state of Cl on LHS is +1 while on RHS is -1. Thus oxidation state is decreasing. So it is reduction.
In option 4, oxidation state of S on both sides is +6, but there is addition of oxygen. So there is oxidation.