Question

for the reaction in question 5, list those elements which have changed oxidation number during the reaction, showing the oxidation number before and after the reaction. Which element is oxidized? Which is reduced? Which is the oxidizing agent? Which is the reducing agent? How many electrons are transferred per sulfur atom? How many totally in the reaction as shown?

5. Balance the following equation: Cl2 + K2S2O3 + KOH KCI + K2SO4 + H20

Answer 1

The balanced reaction is : 4 Cl₂ + K₂S₂O₃ + 10 KOH $\rightarrow$ 8 KCl + 2 K₂SO₄ + 5 H₂O

Elements which changed oxidation numbers

Element	oxidation number before reaction	oxidation number after reaction
Cl	0 (in Cl2)	-1 (in KCl)
S	+2 (in K2S2O3)	+6 (in K2SO4)

Element oxidized : Sulfur

Element reduced : Chlorine

Oxidizing agent : Cl₂

Reducing agent : K₂S₂O₃

Electrons transferred per sulfur atom = (oxidation number after reaction) - (oxidation number before reaction)

Electrons transferred per sulfur atom = (6) - (2)

Electrons transferred per sulfur atom = 4

Total electrons transferred in reaction : (Electrons transferred per sulfur atom) * (number of sulfur atoms)

Total electrons transferred in reaction : (4) * (2)

Total electrons transferred in reaction : 8