Which of the following solutions would have the lowest boiling point?

A.1.0 M NaCl
B.2.0 M NaCl
C.3.0 M NaCl
D.4.0 M NaCl

To determine which of the given solutions would have the lowest boiling point, we need to understand the concept of boiling point elevation and how it relates to the concentration of solutes in a solution.

Boiling point elevation occurs when a solute, such as NaCl, is dissolved in a solvent, such as water. The presence of solute particles disrupts the normal boiling process, causing the boiling point of the solution to be higher than that of the pure solvent. The greater the concentration of solute particles, the greater the boiling point elevation.

Therefore, the solution with the lowest boiling point would be the one with the lowest concentration of NaCl.

Given the concentrations of the solutions provided, the one with the lowest concentration of NaCl is option A: 1.0 M NaCl.

To determine which of the given solutions would have the lowest boiling point, we need to understand the concept of boiling point elevation and colligative properties.

Boiling point elevation is a colligative property, which means it depends on the concentration of solute particles in a solution, not on the identity of the solute itself. The more solute particles present, the higher the boiling point of the solution compared to the pure solvent.

In this case, we have solutions with different concentrations of NaCl, which dissociates into Na+ and Cl- ions in water. NaCl is an ionic compound, so it dissociates completely into its constituent ions in water.

The key idea is that the more ions present in a solution, the greater the boiling point elevation. Therefore, the solution with the highest concentration of NaCl will have the greatest number of solute particles and, consequently, the highest boiling point.

Let's compare the given options:
A. 1.0 M NaCl: This solution contains 1 mole of NaCl per liter, so it will have the lowest boiling point elevation compared to the other options.
B. 2.0 M NaCl: This solution contains 2 moles of NaCl per liter, which means it has a higher concentration of NaCl ions compared to option A. It will have a higher boiling point elevation than option A.
C. 3.0 M NaCl: This solution contains 3 moles of NaCl per liter, which means it has an even higher concentration of NaCl ions compared to options A and B. It will have a higher boiling point elevation than both options A and B.
D. 4.0 M NaCl: This solution contains 4 moles of NaCl per liter, which means it has the highest concentration of NaCl ions among the given options. It will have the highest boiling point elevation compared to options A, B, and C.

Therefore, option A, 1.0 M NaCl, will have the lowest boiling point among the given choices.

delta T = i*Kb*m

Since Kb is constant you want i*m to be the lowest.
i = 2 for NaCl