In the compound CH3COOH (acetic acid), what are the oxidation states of the carbon atoms labeled as (i) in the methyl group (CH3-) and (ii) in the carboxyl group (-COOH)?

• A. (i) 0, (ii) +4
• B. (i) +3, (ii) -3
• C. (i) -1, (ii) +1
• D. (i) -3, (ii) +3

Answer: (D)

Verified step by step guidance

1. Identify the two carbon atoms in acetic acid (CH3COOH): one in the methyl group (CH3-) and one in the carboxyl group (-COOH).
2. Recall the general rules for assigning oxidation states: hydrogen is usually +1, oxygen is usually -2, and the sum of oxidation states in a neutral molecule is zero.
3. For the methyl carbon (CH3-), assign oxidation states by considering that each hydrogen is +1 and carbon balances the total charge. Use the formula: oxidation state of C + 3(+1) = 0, then solve for the carbon's oxidation state.
4. For the carboxyl carbon (-COOH), consider the bonds to oxygen and hydrogen: oxygen is -2, hydrogen is +1, and the carbon's oxidation state balances the sum to zero. Set up the equation: oxidation state of C + (number of O atoms × -2) + (number of H atoms × +1) = 0, then solve for the carbon's oxidation state.
5. Compare the calculated oxidation states for both carbons to the given options to identify the correct oxidation states for the methyl and carboxyl carbons.