I've been given this redox equation to balance:
CH3CH2OH + Cr2O7(2-) --> CH3COOH + Cr(3+)
The 2 half-reactions are:
oxidation of ethanol: CH3CH2OH --> CH3COOH
reduction of acidic dichromate ion: Cr2O7(3-) --> Cr(3+)
What I got was:
Ox: CH3CH2OH + H2O --> CH3COOH + 4H+ + 4e
Re: 14H+ + 9e + Cr2O7(2-) --> 2Cr(3+) + 7H2O
I then added multipled the top equation by 9, the bottom by 4 and then added the 2 equations together to get:
9CH3CH2OH + 4Cr2O7(2-) + 20H+ --> 9CH3COOH + 8Cr(3+) + 19H2O
Does any1 agree with my answer? (I just think the numbers seem a bit big...)