Multiple Choice
Determine the oxidation state of Cr in K2Cr2O7.
6. Chemical Quantities & Aqueous Reactions
Calculate Oxidation Numbers
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What is the oxidation number of arsenic in H₂AsO₄⁻?
A
+1
B
-3
C
+5
D
+3
Verified step by step guidance1
Identify the oxidation number of hydrogen (H) and oxygen (O) in the compound. Hydrogen typically has an oxidation number of +1, and oxygen typically has an oxidation number of -2.
Write the chemical formula for the compound: H₂AsO₄⁻. This indicates there are 2 hydrogen atoms, 1 arsenic atom, and 4 oxygen atoms.
Set up an equation to find the oxidation number of arsenic (As). Let the oxidation number of arsenic be x. The sum of oxidation numbers in a polyatomic ion equals the charge of the ion. Therefore, 2(+1) + x + 4(-2) = -1.
Simplify the equation: 2 + x - 8 = -1. Combine like terms to solve for x.
Solve the equation for x to find the oxidation number of arsenic. This will give you the oxidation number of arsenic in H₂AsO₄⁻.
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