Question

balance the following reactions by the half reaction method in acid

BrO4^- + N2O /   BrO- + NO3-

I2 /IO3^- + I^-

MnO2 + Cl2 /   MnCl2 + ClO-

Answer 1

Balancing the equations,

a) BrO4- + N2O ---> BrO- + NO3-

Balance O,

BrO4- ---> BrO- + 3H2O

Balance H and add e-'s,

BrO4- + 6H+ + 6e- --> BrO- + 3H2O

and,

N2O ---> NO3-

Balance N,

N2O --> 2NO3-

Balance O,

N2O + 5H2O --> 2NO3-

Balance H and add e-'s,

N2O + 5H2O --> 2NO3- + 10H+ + 6e-

Add both equations,

BrO4- + N2O + 2H2O --> BrO- + 2NO3- + 4H+

Is net balanced equation

b) I2 --> IO3- + I-

I2 --> IO3-

Balance I and O,

I2 + 6H2O ---> 2IO3-

Balance H and add e-'s,

I2 + 6H2O --> 2IO3- + 12H+ + 5e-

and,

I2 --> I-

Balance I and add e-'s,

I2 + 2e- --> 2I-

Multiply with 5 and the first equation with 2, add them together,

7I2 + 12H2O --> 4IO3- + 10I- + 24H+

Is net balanced equation

c) MnO2 + Cl2 --> MnCl2 + ClO-

MnO2 --> Mn2+

Balance O,

MnO2 --> Mn2+ + 2H2O

Balance H and add e-,

MnO2 + 4H+ + 2e- --> Mn2+ + 2H2O

and,

Cl2 --> ClO-

Balance Cl and O,

Cl2 + 2H2O --> 2ClO-

Balance H and add e-'s,

Cl2 + 2H2O ---> 2ClO- + 4H+ + 2e-

add both equations

MnO2 + 2H2O --> Mn2+ + 2ClO-

Is net balanced equation