Question

Given two half reactions as follows: A2+ → 2 A2+ + 3 e− 4 e− + B → B4− What would you multiply each half-reaction by, to cancel out the electrons?

Answer 1

In order to cancel the electrons,. the oxidation half reaction must be multiplied by 4 and the reduction half reaction must be multiplied by 3.

Step-by-step explanation:

Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

`X\rightarrow X^(n+)+ne^-`

Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

`X^(n+)+ne^-\rightarrow X`

The half cell reactions for the above reaction follows:

Oxidation half reaction:
`A_(2)^+\rightarrow 2A^(2+)+3e^-`

Reduction half reaction:
`B+4e^-\rightarrow B^(4-)`

Thus, in order to cancel the electrons,. the oxidation half reaction must be multiplied by 4 and the reduction half reaction must be multiplied by 3.

Thus,

4*Oxidation half reaction:
`4A_(2)^+\rightarrow 8A^(2+)+12e^-`

3*Reduction half reaction:
`3B+12e^-\rightarrow 3B^(4-)`

Overall reaction:-

`4A_(2)^++3B\rightarrow 8A^(2+)+3B^(4-)`