Which solution is expected to have the highest boiling point: .20 m KBr or .3 m sugar? Why?
Please explain so i can understand thanks so much!
Please explain so i can understand thanks so much!
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The KBr. KBr is ionic and dissociates when it dissolves in water.
KBr--------------> K+ + Br-
Since there are two ions for every KBr, the effective molality of the solution will be .4 m. The boiling point of the water will be raised by the boiling point constant multiplied by .4 m.
(0.51 deg C kg / mol)(.4 mol / kg)
The sugar is molecular, and does not ionize in solution. The molality will be .3 m and the boiling point elevation will be (0.51 deg C kg/mol)(.3 mol/kg)
KBr--------------> K+ + Br-
Since there are two ions for every KBr, the effective molality of the solution will be .4 m. The boiling point of the water will be raised by the boiling point constant multiplied by .4 m.
(0.51 deg C kg / mol)(.4 mol / kg)
The sugar is molecular, and does not ionize in solution. The molality will be .3 m and the boiling point elevation will be (0.51 deg C kg/mol)(.3 mol/kg)
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KBr has ionic bonds, while sugar contains hydrogen bonding. More energy is required to overcome the intermolecular forces of KBr than sugar because ionic bonds are more resistant to phase change than hydrogen bonding. Therefore, KBr has the higher boiling point.