Question

Following are structural formulas and heats of combustion of acetaldehyde and ethylene oxide. Which of these compounds is more stable? Explain. CC=O COC Acetaldehyde Ethylene oxide \(-1164 \mathrm{~kJ}(-278.8 \mathrm{kcal}) / \mathrm{mol}\) \(-1264 \mathrm{~kJ}(-302.1 \mathrm{kcal}) / \mathrm{mol}\)

Short answer

Answer: Acetaldehyde is more stable.

Step-by-step solution

Identifying the given values

We are given the following information: - Structural formulas of acetaldehyde and ethylene oxide. - Heats of combustion for acetaldehyde: \(-1164 \mathrm{~kJ/mol}\) - Heats of combustion for ethylene oxide: \(-1264 \mathrm{~kJ/mol}\)

Comparing heats of combustion

Let's compare the heats of combustion for both compounds: - Acetaldehyde: \(-1164 \mathrm{~kJ/mol}\) - Ethylene oxide: \(-1264 \mathrm{~kJ/mol}\) The compound with the lowest (least exothermic) heat of combustion would be more stable. In this case, acetaldehyde has a higher (less negative) value, while ethylene oxide has a lower (more negative) value.

Determining the more stable compound

Based on the comparison of the heats of combustion, the more stable compound is the one with the least exothermic heat of combustion. In this case, that is acetaldehyde with \(-1164 \mathrm{~kJ/mol}\). Thus, the more stable compound is acetaldehyde.