Question

Mno4-+Br-1=Mn2++Br2-2
Balance it by oxidation no. method​

Answer 1

Answer:

MnO4- + Br- → MnO2 + BrO3- + OH-  

Mn+7O-24- + Br-1- → Mn+4O-22 + Br+5O-23- + O-2H+1-  

O:Br-1- → Br+5O-23-(Br)

R:Mn+7O-24- → Mn+4O-22(Mn)

O:Br-1- → Br+5O-23-  

R:Mn+7O-24- → Mn+4O-22  

O:Br- → BrO3-  

R:MnO4- → MnO2  

O:Br- + 3H2O → BrO3-  

R:MnO4- → MnO2 + 2H2O  

O:Br- + 3H2O → BrO3- + 6H+  

R:MnO4- + 4H+ → MnO2 + 2H2O  

O:Br- + 3H2O + 6OH- → BrO3- + 6H2O  

R:MnO4- + 4H2O → MnO2 + 2H2O + 4OH-  

O:Br- + 3H2O + 6OH- → BrO3- + 6H2O + 6e-  

R:MnO4- + 4H2O + 3e- → MnO2 + 2H2O + 4OH-  

O:Br- + 3H2O + 6OH- → BrO3- + 6H2O + 6e-| *1

R:MnO4- + 4H2O + 3e- → MnO2 + 2H2O + 4OH-| *2

O:Br- + 3H2O + 6OH- → BrO3- + 6H2O + 6e-  

R:2MnO4- + 8H2O + 6e- → 2MnO2 + 4H2O + 8OH-  

Br- + 2MnO4- + 11H2O + 6OH- + 6e- → BrO3- + 2MnO2 + 10H2O + 6e- + 8OH-

Br- + 2MnO4- + H2O → BrO3- + 2MnO2 + 2OH-

Finally, always check to see that the equation is balanced. First, verify that the equation contains the same type and number of atoms on both sides of the equation.

Second, verify that the sum of the charges on one side of the equation is equal to the sum of the charges on the other side. It doesn't matter what the charge is as long as it is the same on both sides.

1*-1 + 2*-1 + 1*0  =  1*-1 + 2*0 + 2*-1

-3  =  -3

Since the sum of individual atoms on the left side of the equation matches the sum of the same atoms on the right side, and since the charges on both sides are equal we can write a balanced equation.

2MnO4- + Br- + H2O → 2MnO2 + BrO3- + 2OH-