AP Chemistrymediummcq1 pt
In the electrolysis of water, how many moles of electrons are required to produce 0.250 mol of O₂ gas at the anode?
A.1.00 mol
B.0.250 mol
C.0.500 mol
D.0.0625 mol
Explanation
Core Concept
The anode half-reaction is 2 H₂O(l) → O₂(g) + 4 H⁺(aq) + 4 e⁻, so every mole of oxygen gas demands four moles of electrons. Scaling linearly, 0.250 mol O₂ times 4 mol e⁻ per mol O₂ gives 1.00 mol e⁻. Electron balance links the two electrodes because identical charge passes through both.
Correct Answer
A1.00 mol
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