Hint: A key distinction between ideal and non-ideal solutions lies in how closely they follow Raoult’s law. Keeping this in mind, attempt to differentiate these two types of solutions.
Complete step by step answer:
The primary distinction between ideal and non-ideal solutions lies in how they apply Raoult’s law. Let’s begin by understanding what this law states. According to Raoult’s law, the vapor pressure of a solution with a non-volatile solute at a given temperature equals the vapor pressure of the pure solvent at that temperature, multiplied by the solvent’s mole fraction. In mathematical form, it is expressed as:
[latex]P_{\text{solution}} = P^{\circ} \times \chi_{\text{solvent}}[/latex]
Here:
– [latex]P_{\text{solution}}[/latex] is the vapor pressure of the solution.
– [latex]P^{\circ}[/latex] is the vapor pressure of the pure solvent.
– [latex]\chi_{\text{solvent}}[/latex] is the mole fraction of the solvent.
The formula for the mole fraction of the solvent is:
[latex]\chi_{\text{solvent}} = \frac{\text{Moles of solvent}}{\text{Total moles in the solution}}[/latex]
Now, as we have covered the basics we can move on to the differences between ideal and non-ideal solutions.
|
Ideal solution |
Non-ideal solution |
| 1. It follows Raoult’s law as closely as possible. | 1. Does not obey Raoult’s law. |
| 2. The intermolecular forces between solute and solvent particles are identical to those between solvent-solvent particles. | 2. The molecular attraction is different between solute-solvent particles and that between solvent-solvent particles. |
| 3. The fraction of solvent particles transitioning into vapor form stays constant, even after the addition of solute particles.
4. The solvent’s liquid and vapor phases continuously maintain a state of dynamic equilibrium. |
3. The solvent’s vapor pressure drops considerably upon the addition of solute particles. 4. The equilibrium is notably disrupted due to the various natural forces at work. |
| 5. With the addition of more solute particles to the solution, the vapor pressure gradually decreases, resulting in a straight line when represented on a graph. | 5. The decrease in vapour pressure is not in a linear manner. |
| 6.Ideal solutions can turn into non-ideal solutions when solute particles of various sizes are added to the solution. | 6. Non-ideal solutions tend to exhibit characteristics similar to ideal solutions when they are in highly diluted states. |
| 7. When two ideal solutions are mixed, there is no change in enthalpy or volume of the solution. | 7. When two non-ideal solutions are mixed, the change in volume and enthalpy is very significant. |
| 8. For example solutions of benzene-toluene, n hexane- n heptane and ethyl bromide-ethyl iodide. | 8. For example solutions of sugar-water, alkane and kerosene etc. |
Note:
In reality, ideal solutions are impossible to achieve. This is due to various factors that prevent solutions from exhibiting ideal behavior. For a solution to be perfectly ideal, for instance, the solute and solvent particles would need to be identical in size, which only occurs when both solute and solvent are chemically the same compound. However, in that case, it would no longer be considered a solution.