ELECTROCHEMISTRY CLASS-12
REDOX REACTIONS [ELECTRONIC CONCEPT]
- Definitions
(i) OXIDATION :-This reaction involves loss of electron.
(ii) REDUCTION :-This reaction involves gain of electron.
(iii) REDOX REACTION :-This reaction involves both oxidation and reduction, i.e., in this reaction one substance(reactant) is reduced while the other substance (reactant) is oxidized.
(iv) OXIDIZING AGENT (OXIDANT) :-The substance which gets reduced , oxidizes the other substances, is called oxidant.It gains the electron.
(v) REDUCING AGENT (REDUCTANT) :-The substance which gets oxidized , reduces the other substances, is called reductant.It looses the electron.
- Example (i)
Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
Or, In ionic form
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
Zn(s) → Zn2+(aq) + 2e- .....(1) [oxidation],Zn releases 2 electrons to form Zn2+ ion ,
Cu2+(aq) + 2e- → Cu(s) .......(2)[Reduction] Cu2+ ion gains 2 electrons to form Cu
___________________________________on adding
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) .......[Redox reaction]
OXIDANT - Cu2+
REDUCTANT - Zn
- Example (ii)
Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s)
Or, In ionic form
Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s)
Cu(s) → Cu2+(aq) + 2e- .....(1) [oxidation], Cu releases 2 electrons to form Cu2+ ion ,
2Ag+(aq) + 2e- → 2Ag(s) .......(2)[Reduction] Two Ag+ ions gain 2 electrons to form two Ag atoms
_____________________________________on adding
Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s) .......[Redox reaction]
OXIDANT - Ag+
REDUCTANT - Cu
