Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 109	General Chemistry	Spring 2007
Lecture Notes:: Redox Numbers	© R. Paselk 2001
	Answers to Practice Examples

Let's try these rules on some examples:

• NH₄⁺: Rule 1 & 6 4(+1) + N = +1, N = +1 - (+4) = +3
• CO₃^2-: Rule 1 & 5 C + 3(-2) = -2, C = -2 - (-6) = +4
• NO₃^-: Rule 1 & 5 N + 3(-2) = -1, N = -1 -(-6) = -5
• NO₂^-: Rule 1 & 5 N + 2(-2) = -1, N = -1 - (-4) = +3
• PO₄^3-: Rule 1 & 5 P + 4(-2) = -3, P = -3 - (-8) = +5
• SO₃^2-: Rule 1 & 5 S + 3(-2) = -2, S = -2 - (-6) = +4
• SO₄^2-: Rule 1 & 5 S + 4(-2) = -2, S = -2 - (-8) = + 6
• C₂O₄^2-: Rule 1 & 5 2C + 4(-2) = -2, 2C = -2 - (-8) = +6, C = +3
• HCO₃^-: Rule 1 & 3 & 4 C + 3(-2) + 1 = -1, C = -1 - (-6) - (+1) = +4
• MnO₄^-: Rule 1 & 5 Mn + 4(-2) = -1, Mn = -1 - (-8) = +7
• HClO₄: Rule 1 & 5 & 6 +1 + Cl + 4(-2) = 0, Cl = -1 - (-8) = +7
• HClO₃: Rule 1 & 5 & 6 +1 + Cl + 3(-2) = 0, Cl = -1 - (-6) = +5
• HClO₂: Rule 1 & 5 & 6 +1 + Cl + 2(-2) = 0, Cl = -1 - (-4) = +3
• HClO: Rule 1 & 5 & 6 +1 + Cl + (-2) = 0, Cl = -1 - (-2) = +1

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© R A Paselk

Last modified 14 February 2007