Answer : The balanced chemical equation in a acidic solution are,
(a) 
(b) 
(c) 
(d) 
(e) 
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
<u>(a) The given chemical reaction is,</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
In order to balance the electrons, we multiply the reduction reaction by 2 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation will be,

<u>(b) The given chemical reaction is,</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
The electrons in oxidation and reduction reaction are same. Now add both the equation, we get the balanced redox reaction.
The balanced chemical equation in a acidic solution will be,

<u>(c) The given chemical reaction is,</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
In order to balance the electrons, we multiply the oxidation reaction by 5 and reduction reaction by 2 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a acidic solution will be,

<u>(d) The given chemical reaction is,</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
The electrons in oxidation and reduction reaction are same. Now add both the equation, we get the balanced redox reaction.
The balanced chemical equation will be,

<u>(e) The given chemical reaction is,</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
In order to balance the electrons, we multiply the oxidation reaction by 2 and reduction reaction by 3 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a acidic solution will be,
