Q. Show Redox Reactions as Electron Transfer?
Ans.
Oxidation is a process where electrons are lost, and reduction is a process where electrons are gained.
For example, the reaction of sodium with chlorine is a redox reaction.
The equation is 2Na + Cl2 -> 2NaCl
Writing this equation as an ionic equation gives:
2Na + Cl2 -> 2Na+ + 2Cl-
There are two processes taking place:
( i ) Sodium is losing (i.e., producing or donating) an electron to form a Na+ ion:
Na -> Na+ + e-
( ii ) Chlorine is gaining an electron to form a Cl- ion:
Cl + e- -> Cl-
During the above reactions, sodium is said to be oxidized (i.e., it lost an electron).
Chlorine is said to have been reduced (i.e., it gained an electron).
Ionic equations like (i) and (ii) above are called half-reactions (since each is only half of the overall redox reaction). When considering a redox reaction, it is often useful to break it down into its reduction and oxidation half-reactions.