Textbook Question
Calculate the oxidation numbers for the indicated atoms.
(c)
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13. Alcohols and Carbonyl Compounds
Oxidizing and Reducing Agents
Problem 4e
Textbook Question
Determine the oxidation number of each carbon indicated by an arrow.
(e) 
Verified step by step guidance1
Identify the structure: The molecule shown is formaldehyde, with the chemical formula CH2O. The carbon atom is double-bonded to an oxygen atom and single-bonded to two hydrogen atoms.
Assign oxidation numbers to hydrogen: In organic compounds, hydrogen is typically assigned an oxidation number of +1.
Assign oxidation numbers to oxygen: Oxygen is typically assigned an oxidation number of -2 in organic compounds.
Calculate the oxidation number for carbon: Let the oxidation number of carbon be x. The sum of the oxidation numbers in a neutral molecule must equal zero. Therefore, the equation is: x + 2(+1) + (-2) = 0.
Solve for x: Simplify the equation to find the oxidation number of the carbon atom. This will give you the oxidation number of the carbon atom in formaldehyde.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Oxidation Number
The oxidation number, or oxidation state, is a theoretical charge assigned to an atom in a molecule based on the assumption that electrons in a bond are completely transferred to the more electronegative atom. It helps in understanding the electron distribution in compounds and is crucial for determining redox reactions. Oxidation numbers can be positive, negative, or zero, and they follow specific rules for calculation.
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Carbon's Valency and Bonding
Carbon has a valency of four, meaning it can form four covalent bonds with other atoms. The type of bonds (single, double, or triple) and the atoms carbon is bonded to influence its oxidation state. Understanding carbon's bonding behavior is essential for determining its oxidation number in various organic compounds.
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Electronegativity
Electronegativity is the tendency of an atom to attract electrons in a chemical bond. In determining oxidation numbers, the relative electronegativities of the atoms involved are considered; the more electronegative atom is assigned a negative oxidation state, while the less electronegative atom is assigned a positive state. This concept is vital for accurately calculating the oxidation states of carbon in different molecular contexts.
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