Multiple Choice
In the reaction 2Fe2O3 + 3C → 4Fe + 3CO2, what is being oxidized?
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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 state of Cl in the ion ClO3^-?
A
-1
B
+3
C
+1
D
+5
Verified step by step guidance1
Identify the overall charge of the ion, which is given as -1 for ClO3⁻.
Recall that oxygen almost always has an oxidation state of -2 in compounds (except in peroxides or when bonded to fluorine).
Set up an equation for the sum of oxidation states: let the oxidation state of chlorine be x. Since there are 3 oxygen atoms, their total contribution is 3 × (-2) = -6.
Write the equation for the sum of oxidation states equal to the ion charge: x + (-6) = -1.
Solve the equation for x to find the oxidation state of chlorine: x = -1 + 6.
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