Question

the surface tension of the alcohol propanol in air has a value of 23.70 units and the surface tension of water in air is 72.80 units. which two statements are true?
a. propanol will have a higher boiling point than water because the forces between the molecules are greater.
b. propanol will have a more curved meniscus than water because the forces between the molecules are greater.
c. propanol will have a lower boiling point than water because the forces between the molecules are smaller.
d. propanol will have a flatter meniscus than water because the forces between the molecules are smaller.

Explanation:

• Surface tension is related to the intermolecular forces. Higher surface tension means stronger intermolecular forces. Water has higher surface tension (72.80 units) than propanol (23.70 units), so water has stronger intermolecular forces.
• Boiling point is also related to intermolecular forces. Stronger intermolecular forces lead to a higher boiling point. Since water has stronger intermolecular forces, propanol will have a lower boiling point (so statement C is true).
• Meniscus curvature: Stronger intermolecular forces (higher surface tension) lead to a more curved meniscus. Since water has higher surface tension (stronger intermolecular forces), propanol (with weaker intermolecular forces) will have a flatter meniscus (so statement D is true).

Answer:

C. Propanol will have a lower boiling point than water because the forces between the molecules are smaller.
D. Propanol will have a flatter meniscus than water because the forces between the molecules are smaller.