Question

C2 T13HW Question 4 Homework. Unanswered What is the sum of the coefficients when the following redox reaction is properly balanced? H:0(1) + Br (aq) + AL Alls) + Broj (aq) + (aq) Numeric Answer:

Answer 1

Br in Br- has oxidation state of -1

Br in BrO3- has oxidation state of +5

So, Br in Br- is oxidised to BrO3-

Al in Al+3 has oxidation state of +3

Al in Al has oxidation state of 0

So, Al in Al+3 is reduced to Al

Reduction half cell:

Al+3 + 3e- --> Al

Oxidation half cell:

Br- --> BrO3- + 6e-

Balance number of electrons to be same in both half reactions

Reduction half cell:

2 Al+3 + 6e- --> 2 Al

Oxidation half cell:

Br- --> BrO3- + 6e-

Lets combine both the reactions.

2 Al+3 + Br- --> 2 Al + BrO3-

Balance Oxygen by adding water

2 Al+3 + Br- + 3 H2O --> 2 Al + BrO3-

Balance Hydrogen by adding H+

2 Al+3 + Br- + 3 H2O --> 2 Al + BrO3- + 6 H+

This is balanced chemical equation in acidic medium

Sum of coefficients = 2 + 1 + 3 + 2 + 1 + 6

= 15

Answer: 15