Question

Balance this reaction, show all steps? (Answer given)

AsO3 (-3) + MnO4 (-1) ----> AsO4 (-3) + Mn (2+)

Answer:

5AsO3 + 2MnO4 + 6H+ ---> 5AsO4 + 2Mn + 3H2O

Please show the steps in between like the half reactions and balancing them. Thanks

Answer 1

The unbalanced equation is

Write the oxidation numbers

Divide the equation in oxidation and reduction half reactions.

............. oxidation

................reduction

Since the oxidation number of As increases from +3 to +5, it is oxidised.

Since the oxidation number of Mn decreases from +7 to +2, it is reduced.

As atoms are balanced in oxidation half reaction. Balance O atoms by adding one water molecule to left hand side of the equation.

Balance H atoms by adding 2 protons on right hand side.

.

Balance the charges by adding two electrons to the right side.

..............(1)

In the reduction half reaction, Mn atoms are balanced. Balance O atoms by adding 4 water molecules to right hand side.

Balance H atoms by adding 8 protons to left hand side

Balance charges by adding 5 electrons to left hand side.

.........(2)

Multiply equation (1) with 5 and equation (2) with 2

Add above two equations

This is the balanced redox reaction.