Question

the table above shows the structural formulas and molar masses for three different compounds. which of the following is a list of the compounds in order of increasing boiling points?
(a) butane < 1 - propanol < acetone
(b) butane < acetone < 1 - propanol
(c) 1 - propanol < acetone < butane
(d) acetone = butane < 1 - propanol

Explanation:

Step1: Analyze intermolecular forces

• Butane has only weak London dispersion forces.
• Acetone has dipole - dipole forces in addition to London dispersion forces.
• 1 - propanol has hydrogen bonding (strongest intermolecular force among the three) along with London dispersion and dipole - dipole forces.

Step2: Relate intermolecular forces to boiling point

• Stronger intermolecular forces lead to higher boiling points.
• Since London dispersion forces < dipole - dipole forces < hydrogen bonding.

Step3: Compare boiling points

• Butane (only London dispersion) has the lowest boiling point.
• Acetone (dipole - dipole + London dispersion) has a higher boiling point than butane.
• 1 - propanol (hydrogen bonding + dipole - dipole + London dispersion) has the highest boiling point.

Answer:

B. Butane < acetone < 1 - propanol