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Using the half cell method to balance a redox reaction

Balance the following redox reaction using the half cell method for balancing redox reactions:

KClO_3(aq) + HBr(aq) -----> Br2(l) + H_2O(l) + KCl

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Please see attachment for detailed tutorial and solution. The attachment is copied below in case there are problems opening the attachment, but the attachment is much easier to read, as the subscripts and superscripts are correct.

Problem: Balance the following redox reaction:

KClO3(aq) + HBr(aq) -----> Br2(l) + H2O(l) + KCl(aq)

When balancing a redox reaction, there are several steps that need to be followed. This is because we not only have to balance the number of elements on each side of the reaction, as is necessary when balancing all other reactions, but we also have to balance the electrons transferred.

The aim of this tutorial is to demonstrate the half-cell method of balancing equations. The steps that you want to follow to balance this equation are as follows.

In acidic solution:

Balance all non-hydrogen and non-oxygen atoms in the equation.

In our reaction, this is done by placing a 2 in front of the HBr. Remember that when balancing, we can only alter coefficients, NOT subscripts.

KClO3(aq) + 2HBr(aq) -----> Br2(l) + H2O(l) + KCl(aq)

Split your reaction into two half reactions. You should consider the species oxidized and the species reduced in two separate reactions.

The two half-reactions for our reaction are:
KClO3(aq) ----> KCl(aq)


2 HBr(aq) -----> ...

Solution Summary

The expert uses the half cell method to balance a redox reaction.