6K.1

[Tracy Tolentino_2E]

The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in blood: H+ (aq) + Cr2O7^2- (aq) + C2H5OH(aq) ---> Cr^3+ (aq) + C2H4O(aq) + H2O(l)
Identify the elements undergoing oxidation or reduction and indicate their initial and final oxidation numbers. (b) Write and balance the oxidation half-reaction. (c) Write and balance
the reduction half-reaction. (d) Combine the half-reactions to produce a balanced redox equation.

When writing the half reactions, how would I incorporate the H2O and H+ that are part of the reaction equation?

[Brooke Yasuda 2J]

You add H2O molecules in order to balance the number of oxygens that are on both sides of the reaction. After you balance the number of Oxygen molecules you balances the number of Hydrogens with H+. After doing this, you finally balance charge by adding electrons to the respective sides of the reaction.

[Grace Jansen 2A]

For every 1 H2O you add, you have to add 2H+ to the other side. Additionally, make sure all of the other elements are balanced before you balance the oxygen and hydrogen!