What has the lowest surface tension and why? CH3CH2CH2CH3, (CH3)2CO, C6H6, H20

which has the weakest intermolecular bond (C6H6) Why?

Butane has the lowest, but why?

To determine which compound has the lowest surface tension among CH3CH2CH2CH3 (butane), (CH3)2CO (acetone), C6H6 (benzene), and H2O (water), we need to understand what surface tension is and the factors that influence it.

Surface tension is the measure of how difficult it is to break or stretch the surface of a liquid. It is caused by the cohesive forces between the liquid molecules, which are responsible for the strong attraction between the molecules at the surface. The higher the cohesive forces, the higher the surface tension.

Factors that affect surface tension include intermolecular forces, molecular size, molecular shape, and temperature. Generally, substances with stronger intermolecular forces and smaller molecular size tend to have higher surface tension.

Now, let's evaluate each compound:

1. CH3CH2CH2CH3 (butane): Butane is a nonpolar molecule composed of only carbon and hydrogen atoms. It exhibits weak London dispersion forces between its molecules. While London dispersion forces are relatively weak, they are present in all molecules. Therefore, butane can have some level of surface tension, albeit relatively low compared to other compounds.

2. (CH3)2CO (acetone): Acetone is also a molecule composed of carbon, hydrogen, and oxygen atoms. It is a polar molecule due to the presence of the carbonyl group, which creates a partial positive charge on the carbon atom and a partial negative charge on the oxygen atom. The dipole-dipole interactions in acetone contribute to its intermolecular forces and can lead to higher surface tension compared to nonpolar molecules like butane.

3. C6H6 (benzene): Benzene consists of a ring of carbon atoms with alternating single and double bonds. It is a nonpolar molecule and exhibits weak London dispersion forces. Similar to butane, benzene's surface tension will be relatively low due to its nonpolar nature and weak intermolecular forces.

4. H2O (water): Water is a highly polar molecule with a bent molecular shape. It exhibits strong hydrogen bonding between its molecules, which are responsible for its various unique properties, including high surface tension. Hydrogen bonds are stronger than other intermolecular forces, resulting in water having a significantly higher surface tension compared to the other compounds mentioned.

In summary, among the given compounds, H2O (water) has the highest surface tension due to its strong hydrogen bonding. (CH3)2CO (acetone) would have a moderate surface tension because of polar dipole-dipole interactions. CH3CH2CH2CH3 (butane) and C6H6 (benzene) would have relatively lower surface tensions due to weak London dispersion forces and nonpolar nature.