Which Compound Has The Highest Vapor Pressure at 25°C?
What compound has the highest vapor pressure at 25°C?
The compound with the highest vapor pressure at 25°C is option a. CH3CH2OH (ethanol). Vapor pressure is a measure of the tendency of a substance to evaporate. Higher vapor pressure indicates a higher tendency to evaporate. Among the given options, ethanol (CH3CH2OH) has the highest vapor pressure at 25°C. This is because ethanol has intermolecular hydrogen bonding, which leads to stronger attractions between its molecules. These stronger attractions make it easier for ethanol molecules to escape from the liquid phase and enter the gas phase, resulting in a higher vapor pressure compared to the other compounds. In contrast, the other options (b. CH2OCH3, c. CH3CH2CH3, d. CH3CH2CH2Cl) do not exhibit intermolecular hydrogen bonding to the same extent, resulting in weaker intermolecular forces and lower vapor pressures at the same temperature. Therefore, option a. CH3CH2OH (ethanol) has the highest vapor pressure at 25°C.
Understanding Vapor Pressure:
Vapor Pressure: Vapor pressure is a measure of the tendency of a substance to evaporate. At a given temperature, substances with higher vapor pressures evaporate more readily than those with lower vapor pressures.
Intermolecular Hydrogen Bonding:
Hydrogen Bonding: Intermolecular hydrogen bonding occurs when hydrogen atoms in a molecule are attracted to electronegative atoms in neighboring molecules. This type of bonding leads to stronger attractions between molecules.
Effect on Vapor Pressure:
Higher Vapor Pressure: Substances with stronger intermolecular forces, such as those with hydrogen bonding, tend to have higher vapor pressures at a given temperature. This is because the molecules can more easily break free from the liquid phase and enter the gas phase.
By understanding the concept of vapor pressure and intermolecular forces, we can determine which compound has the highest vapor pressure at a specific temperature.