balancing acidic redox reaction, the oxidation of ethanol by dichromate ion in acidic solution, producing chromium (III) ion, and acetaldehyde (CH3CHO) as products: The breathalyzer test!)
C2H5OH + Cr2O7^2- ---> Cr^3+ + CH3CHO
I've been going through this for an hour and I think my issue is I'm probably balancing the oxidation states in the beginning incorrectly. Please help me. Please...
C2H5OH + Cr2O7^2- ---> Cr^3+ + CH3CHO
I've been going through this for an hour and I think my issue is I'm probably balancing the oxidation states in the beginning incorrectly. Please help me. Please...
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Start with the ethanol-ethanal reaction.
Balance the O's by adding water, balance the H's by adding H+, balance the charge by adding e- and you get:
C2H5OH ----> CH3CHO + 2H+ + 2e-
Then same thing with the dichromate reaction
[Cr2O7]2- + 14H+ + 6e- ----> 2Cr3- + 7H2O
(Charge balance: (2-) + (14+) + (6-) = 2x(3+)
The ethanol reaction produces 2e-; the dichromate reaction requires 6e- so the ethanol reaction gets multiplied by 3.
3C2H5OH + [Cr2O7]2- + 14H+ + 6e- ----> 3CH3CHO + 6H+ + 6e- + 2Cr3- + 7H2O
Add out the 6e- on both sides,
Add out 6H+ on both sides, leaving 8H+ on the left side.
And I think that's it.
Balance the O's by adding water, balance the H's by adding H+, balance the charge by adding e- and you get:
C2H5OH ----> CH3CHO + 2H+ + 2e-
Then same thing with the dichromate reaction
[Cr2O7]2- + 14H+ + 6e- ----> 2Cr3- + 7H2O
(Charge balance: (2-) + (14+) + (6-) = 2x(3+)
The ethanol reaction produces 2e-; the dichromate reaction requires 6e- so the ethanol reaction gets multiplied by 3.
3C2H5OH + [Cr2O7]2- + 14H+ + 6e- ----> 3CH3CHO + 6H+ + 6e- + 2Cr3- + 7H2O
Add out the 6e- on both sides,
Add out 6H+ on both sides, leaving 8H+ on the left side.
And I think that's it.
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Simplify cant help if we cant understand