Question

Which of the following has the highest boiling point?

• A. 1% urea solution
• B. 1% sucrose
• C. 1% NaCl solution
• D. 1% CaCl\(_2\) solution

Hint:

For solutions, the more ions produced by dissociation, the greater the boiling point elevation.

Answer 1

The Correct Option is D

Step 1: Understanding boiling point elevation.
Boiling point elevation is directly proportional to the molality of the solution. Ionic compounds, such as CaCl\(_2\), dissociate into more particles in solution, which leads to a higher boiling point.

Step 2: Analyzing the options.
(A) 1% urea solution: Urea is a non-electrolyte and does not dissociate into ions, leading to a lower boiling point elevation.
(B) 1% sucrose: Sucrose is also a non-electrolyte, similar to urea, and does not dissociate into ions.
(C) 1% NaCl solution: Sodium chloride dissociates into Na\(^+\) and Cl\(^-\) ions, raising the boiling point more than urea and sucrose, but not as much as CaCl\(_2\).
(D) 1% CaCl\(_2\) solution: Calcium chloride dissociates into three ions (Ca\(^{2+}\) and 2Cl\(^-\)), leading to the highest boiling point elevation.

Step 3: Conclusion.
The correct answer is (D) 1% CaCl\(_2\) solution, as it dissociates into the most ions, resulting in the highest boiling point.