Hydrogen peroxide can act as a reductant according to the half equation
O2(g) + 2H+(aq) + 2e− → H2O2(aq); E° = +0.68 V
Which of the following could all be reduced by hydrogen peroxide?
A - VCE - SSCE Chemistry - Question 19 - 2002 - Paper 1
Question 19
Hydrogen peroxide can act as a reductant according to the half equation
O2(g) + 2H+(aq) + 2e− → H2O2(aq); E° = +0.68 V
Which of the following could all be reduced b... show full transcript
Worked Solution & Example Answer:Hydrogen peroxide can act as a reductant according to the half equation
O2(g) + 2H+(aq) + 2e− → H2O2(aq); E° = +0.68 V
Which of the following could all be reduced by hydrogen peroxide?
A - VCE - SSCE Chemistry - Question 19 - 2002 - Paper 1
Step 1
A. Fe2+(aq), Cu(s), I−(aq)
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Answer
Fe2+ can be reduced by H2O2 as its reduction potential is favorable. Cu(s) cannot be reduced by H2O2 as it is in elemental form and does not exist in an aqueous state as a cation in this context, and I-(aq) can also be reduced by H2O2. Thus, not all can be reduced.
Step 2
B. Ag+(aq), Br2(aq), H2O2(aq)
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Answer
Ag+ can indeed be reduced to Ag(s) by H2O2. Br2 can also be reduced under certain conditions, but H2O2 being a reducing agent does not apply here since it is the same species mentioned as the reactant. Hence, this option is valid.
Step 3
C. Ag(s), Br(aq), Fe2+(aq)
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Since Ag(s) is already in elemental form, it cannot be reduced further. Br(aq) contains bromine in its reactive state which could also be oxidized, but Fe2+ can be reduced. Therefore, this option is invalid.
Step 4
D. I2(s), Cu2+(aq), Fe2+(aq)
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Answer
Both Cu2+ and Fe2+ ions can be reduced by H2O2, and I2 can also be reduced back to I−. Thus, this group can all be reduced by hydrogen peroxide.
