Minimum elevation in boiling point is given by a solution of

1. 0.1M Urea
2. 0.1 NaCL
3. 0.1 Mgcl2
4. 0.1M AL2(So4)3

delta T (increase in b.p.) = i*Kb*m

All are the same m so that is a constant. kb is a constant. Threfore, it all depends upon i, the van't Hoff factor.
i = 1 for urea
i = 2 for NaCl
i = 3 for MgCl2
i = 5 for Al2(SO4)3.

So which will cause the SMALLEST CHANGE?

. 0.1M Urea

To determine which solution among 0.1M Urea, 0.1M NaCl, 0.1M MgCl2, and 0.1M Al2(SO4)3 has the minimum elevation in boiling point, we need to consider the concept of boiling point elevation.

Boiling point elevation refers to the increase in the boiling point of a solvent caused by the addition of a solute. This effect occurs due to the lower vapor pressure of the solvent caused by the presence of the solute particles.

According to Raoult's law, the change in boiling point (ΔTb) is directly proportional to the molality of the solute (m) and the boiling point elevation constant (Kb):

ΔTb = Kb * m

The boiling point elevation constant (Kb) is specific to each solvent and can be found in reference books or online sources.

Now, let's analyze the given solutions:

1. 0.1M Urea: Urea is a non-ionic solute, meaning it does not dissociate into ions when dissolved. Therefore, it does not contribute any ions to the solution. As a result, the boiling point elevation will be relatively small.

2. 0.1M NaCl: Sodium chloride (NaCl) dissociates into Na+ and Cl- ions when dissolved in water. These ions increase the number of solute particles in the solution, thereby increasing the boiling point elevation compared to a non-dissociating solute like urea.

3. 0.1M MgCl2: Magnesium chloride (MgCl2) also dissociates into Mg2+ and 2Cl- ions when dissolved in water. Compared to NaCl, it has more solute particles in solution, resulting in a higher boiling point elevation.

4. 0.1M Al2(SO4)3: Aluminum sulfate (Al2(SO4)3) dissociates into 2Al3+ and 3SO4^2- ions when dissolved. Similar to the previous cases, the presence of more ions causes a greater increase in boiling point.

Considering the given information and the concept of boiling point elevation, the solution with the minimum elevation in boiling point is 0.1M Urea because it does not dissociate into ions and has the lowest number of solute particles.

It is important to note that this explanation assumes that the solutions are all in the same solvent. Boiling point elevation depends on the concentration and nature of both the solute and the solvent.