Question

Balance the following redox reaction if it occurs in basic solution. What are the coefficients in front of Br₂ and OH^- in the balanced reaction?

Br₂(l) → BrO₃^-(aq) + Br^-(aq)

Balance the following redox reaction if it occurs in basic solution. What are the coefficients in front of Br₂ and OH^- in the balanced reaction?

Br₂(l) → BrO₃^-(aq) + Br^-(aq)

options:

Br₂ = 3, OH^- = 6

Br₂ = 2, OH^- = 5

Br₂ = 1, OH^- = 6

Br₂ = 3, OH^- = 3

Br₂ = 1, OH^- = 2

Answer 1

Br2(l) → BrO3 -(aq) + Br-(aq)

split

Br2 = BrO3-

Br2 = Br-

balance atoms other than O

Br2 = 2BrO3-

Br2 = 2Br-

Balance O adding H2O

6H2O + Br2 = 2BrO3-

Br2 = 2Br-

balance H adding H+

6H2O + Br2 = 2BrO3- + 12H+

Br2 = 2Br-

balance charges

6H2O + Br2 = 2BrO3- + 12H+ +10e-

2e- + Br2 = 2Br-

balance-

6H2O + Br2 = 2BrO3- + 12H+ +10e-

10e- + 5Br2 = 10Br-

add all

10e- + 5Br2 + 6H2O + Br2 = 2BrO3- + 12H+ +10e- + 10Br-

cancel common terms

6Br2 + 6H2O = 2BrO3- + 12H+ + 10Br-

add OH- for neutralization

12OH- + 6Br2 + 6H2O = 2BrO3- + 12H+ + 10Br-+12OH-

12OH- + 6Br2 + 6H2O = 2BrO3- + 12H2O + 10Br-

cancle water

12OH- + 6Br2= 2BrO3- + 6H2O + 10Br-

divide by 2

6OH- + 3Br2= BrO3- + 3H2O + 5Br-

so

answer is 3,6