Multiple Choice
Assign an oxidation number to each atom in the compound K₂CrO₄.
6. Chemical Quantities & Aqueous Reactions
Calculate Oxidation Numbers
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
What is the oxidation half-equation for the reaction between aluminium and oxygen in the formation of Al2O3?
A
O2 → O^2- + 2e^-
B
Al → Al^3+ + 3e^-
C
O2 + 4e^- → 2O^2-
D
Al^3+ + 3e^- → Al
Verified step by step guidance1
Identify the species being oxidized in the reaction. In this case, aluminium (Al) is being oxidized.
Write the oxidation half-equation for aluminium. Start with the aluminium atom on the reactant side: Al.
Determine the oxidation state change. Aluminium goes from 0 in Al to +3 in Al^3+. This means it loses 3 electrons.
Express the loss of electrons in the half-equation. Add the electrons to the product side: Al → Al^3+ + 3e^-.
Ensure the equation is balanced in terms of both mass and charge. The number of atoms and the total charge should be the same on both sides of the equation.
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Calculate Oxidation Numbers practice set
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