Name: Non-ideal Solutions
Uploaded: 2019-07-19
Duration: 8 min 43 s
Description: We know that an ideal solution is a theoretical concept. So, what are non-ideal solutions? Why do they show a deviation from Raoult's law? Let's explore!

Question

Draw a graph for an ideal solution formed from solute and solvent(binary liquid solution).

Accepted Answer

The solutions which obey Raoult's law are called ideal solutions. In the binary solution of volatile liquid, the vapour phase consists of vapours of both the components. The Raoult's law for such binary solution may be stated as.

“At a given temperature, for a solution of volatile liquids, the partial pressure of each component is directly proportional to its mole fraction.”

Suppose a binary solution consists of two volatile liquids A and B. If P_A and P_B are the partial vapour pressure of the two liquids and x_A and x_B are their mole fraction in solution, then

$P_{A} \propto x_{A} \Rightarrow P_{A} = P_{A}^{o} x_{A}$

$P_{B} \propto x_{B} \Rightarrow P_{B} = P_{B}^{o} x_{B}$

Where $P_{A}^{o} and P_{B}^{o}$ are the vapour pressures of pure components A and B, respectively. This relationship is called Raoult's law. It states that for a solution of two or more miscible volatile liquids, the partial vapour pressure of each component of the solution at a particular temperature is directly proportional to its mole fraction. According to Raoult's law:

$P = P_{A} + P_{B} = P_{A}^{o} x_{A} + P_{B}^{o} x_{B}$

Draw a graph for an ideal solution formed from solute and solvent(binary liquid solution).

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