Question

Почему температуры кипения спиртов выше, чем у соответствующих по молекулярной массе углеводородов (С2Н5ОН, Мr = 46, tкип = 78 °С; С3Н8, Мr = 44, tкип = –42 °С)?

Answer 1

Ответ:

Это из-за того, что в спиртах водородная связь, именно из-за этого молекулы скреплены между собой сильнее, нежели молекулы углеводородов

Answer 2

Explanation of the Higher Boiling Points of Alcohols Compared to Hydrocarbons

Alcohols have higher boiling points compared to hydrocarbons of similar molecular weight due to the presence of hydrogen bonding in alcohols.

Hydrogen Bonding in Alcohols: - Alcohols have a hydroxyl (-OH) functional group, which allows them to form hydrogen bonds with other alcohol molecules. - This intermolecular hydrogen bonding results in stronger attractive forces between alcohol molecules, requiring more energy to break these bonds and transition from liquid to gas phase.

Comparison with Hydrocarbons: - Hydrocarbons, such as propane (C3H8), lack the hydroxyl functional group and therefore do not exhibit hydrogen bonding to the same extent as alcohols. - As a result, hydrocarbons have weaker intermolecular forces, leading to lower boiling points compared to alcohols of similar molecular weight.

Specific Example: - For instance, ethanol (C2H5OH) has a molecular weight (Mr) of 46 and a boiling point of 78°C, while propane (C3H8) has a lower molecular weight of 44 and a boiling point of -42°C. - The higher boiling point of ethanol compared to propane can be attributed to the presence of hydrogen bonding in ethanol, which results in stronger intermolecular forces and a higher boiling point.

(Source 1)(Source 2)(Source 3)