Question

Which of the following aqueous solutions is predicted to have the highest boiling point?

1) Sodium chloride (NaCl)
2) Glucose (C₆H₁₂O₆)
3) Ethanol (C₂H₅OH)
4) Acetic acid (CH₃COOH)

Answer 1

A 1.00 m NaCl solution will have a boiling point of about 101.02°C.

Step-by-step explanation:

According to Table 11.5.1, the molal boiling point elevation constant for water is 0.51°C/m. Thus a 1.00 m aqueous solution of a nonvolatile molecular solute such as glucose or sucrose will have an increase in boiling point of 0.51°C, to give a boiling point of 100.51°C at 1.00 atm. The increase in the boiling point of a 1.00 m aqueous NaCl solution will be approximately twice as large as that of the glucose or sucrose solution because 1 mol of NaCl produces 2 mol of dissolved ions. Hence a 1.00 m NaCl solution will have a boiling point of about 101.02°C.