Question

If the fugacity of a pure component at the conditions of an ideal solution is 40 bar and its mole fraction is 0.4, what is its fugacity in the solution according to the Lewis-Randall rule?

Answer 1

Answer : The fugacity in the solution is, 16 bar.

Explanation : Given,

Fugacity of a pure component = 40 bar

Mole fraction of component  = 0.4

Lewis-Randall rule : It states that in an ideal solution, the fugacity of a component is directly proportional to the mole fraction of the component in the solution.

Now we have to calculate the fugacity in the solution.

Formula used :

$f_i=X_i\times f_i^o$

where,

$f_i$ = fugacity in the solution

$f_i^o$ = fugacity of a pure component

$X_1$ = mole fraction of component

Now put all the give values in the above formula, we get:

$f_i=0.4\times 40\text{ bar}$

$f_i=16\text{ bar}$

Therefore, the fugacity in the solution is, 16 bar.