Final answer:
Two true statements from the given options are that isopropyl alcohol boils more easily than water, and water has a higher surface tension than vegetable oil.
Step-by-step explanation:
The given question asks which two statements about the substances in the experiment are true, focusing on surface tension and boiling points of liquids. After evaluating the options:
- Adding salt to water increases the surface tension: This is true as salt ions disrupt the hydrogen bonds in water, leading to an increase in surface tension.
- Isopropyl alcohol boils more easily than water: This statement is true because isopropyl alcohol has weaker intermolecular forces compared to water's hydrogen bonds, thus having a lower boiling point.
- Water has a higher surface tension than vegetable oil: This is true, attributable to water's strong hydrogen bonds compared to the weaker van der Waals forces in vegetable oil.
- Adding soap to water increases the surface tension: This is false because soap acts as a surfactant, reducing water's surface tension.
Therefore, the correct answers are:
- B. Isopropyl alcohol boils more easily than water.
- C. Water has a higher surface tension than vegetable oil.