MnO2+HCl→MnCl2+H2O+Cl2
Ionic equation,
MnO2+H++Cl−→Mn2++H2O+Cl2
1st step: Splitting into two half reactions,
Cl−→Cl2(Oxidationhalfreaction); MnO2+H+→Mn2++H2O(Reductionhalfreaction)
2nd step: Adding H+ ions to the side deficient in hydrogen,
Cl−→Cl2;MnO2+4H+→Mn2++2H2O
3rd step: Making atoms equal on both sides,
2Cl−→Cl2;MnO2+4H+→Mn2++2H2O
4th step: Adding electrons to the side deficient in electrons,
2Cl−→Cl2+2e
MnO2+4H++2e→Mn2++2H2O
5th step: Adding both the half reactions,
2Cl−+MnO2+4H+→Cl2+Mn2++2H2O
Converting it into molecular form,
MnO2+2Cl−+4H++2Cl−→Cl2+Mn2++2Cl−+2H2O
or
MnO2+4HCl→MnCl2+Cl2+2H2O