What is the oxidation number of oxygen in CO (carbon monoxide)?

• A. -1
• B. 0
• C. -2
• D. +2

Answer: (A)

Verified step by step guidance

1. Recall the general rules for assigning oxidation numbers: oxygen usually has an oxidation number of -2 in most compounds, except in peroxides where it is -1, and in compounds with fluorine where it can be positive.
2. Write down the chemical formula of carbon monoxide: CO. It consists of one carbon atom and one oxygen atom.
3. Assign the oxidation number of carbon as x and oxygen as y. The sum of oxidation numbers in a neutral molecule must be zero, so set up the equation: x + y = 0.
4. Use the common oxidation number of oxygen (-2) as a starting point and check if it balances with carbon's oxidation number. If it doesn't, consider other possible oxidation states for oxygen.
5. Solve the equation for y (oxygen's oxidation number) by substituting the known or assumed oxidation number of carbon and ensuring the total charge is zero. This will give you the oxidation number of oxygen in CO.