Answer :
(8) The number of electrons added to balance the reaction should be, Two electrons.
(9) The correct option is, (oxidized) and (reduced)
Explanation :
(8) The given oxidation half-reaction is,
The given oxidation half-reaction is an unbalanced reaction because in this reaction the charges are not balanced. So, in order to balance the half reaction we are adding two electrons on product side of the reaction and the oxidation means loss of electrons.
Thus, the balanced oxidation half-reaction will be,
Hence, the number of electrons added to balance the reaction should be, Two electrons.
(9) 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.
The given oxidation-reduction reaction is :
The oxidation-reduction half reaction will be :
Oxidation :
Reduction :
In this reaction, the oxidation state of 'I' changes from (-1) to (0) that means 'I' lost 2 electrons and it shows oxidation and the oxidation state of 'I' changes from (+5) to (0) that means 'I' gains 2 electrons and it shows reduction.
Hence, the correct option is, (oxidized) and (reduced)