Chapter 19, Problem 70A

Interpretation Introduction

Interpretation: The given redox reaction is to be balanced using a half-reaction method.

Concept Introduction :

A half-reaction method to balance the ionic equation in acidic solution involves:-

• Assign the oxidation number to each element.
• Check which element is oxidized and which element is reduced. Write oxidation and reduction half-reactions.
• Check the change in oxidation number for the elements which are oxidized and reduced.
• Then add enough hydrogen ions and water molecules to the equation to balance hydrogen atoms on both sides.
• Adjust the coefficients so that number of electrons lost in oxidation is equal to electrons gained in reduction.
• Add the balanced half-reactions.

Answer to Problem 70A

A balanced equation in ionic form

  

A balanced equation in given form

  

Explanation of Solution

The given redox reaction is:

  

A reaction in the ionic form:

  

Assigning the oxidation number-

  

The oxidation numbers of atoms show that

is oxidized and is reduced.

Change in oxidation number of

Change in oxidation number of

  

  

Balancing the atoms and charges:

  

  

Now, adding both reactions after multiplying reduction half cell reaction with 2

  

Conclusion

A balanced equation in ionic form

  

A balanced equation in given form