Question

If 0.12 mol of solute is in 80 g water calculate the mole fraction of the solute as well as water in solution

Answer 1

$\large{\bf{\gray{\underline{\underline{\orange{Given:}}}}}}$

Moles of solute = 0.12

Mass of water = 80g

$\large{\bf{\gray{\underline{\underline{\green{To\:Find:}}}}}}$

We have to find mole fraction of solute and solvent.

$\large{\bf{\gray{\underline{\underline{\pink{Solution:}}}}}}$

◈ Mole fraction is defined as the ratio of number of moles of one component to the total number of moles of all the components.

Formula :

$\dag\:\boxed{\bf{\red{x_A=\dfrac{n_A}{n_A+n_B}}}}$

Let's calculate :

Moles of water = 80/18 = 4.44

⛥ Mole fraction of solute :

$:\implies\tt\:x_s=\dfrac{n_s}{n_s+n_w}$

$:\implies\tt\:x_s=\dfrac{0.12}{0.12+4.44}$

$:\implies\tt\:x_s=\dfrac{0.12}{4.56}$

$:\implies\boxed{\bf{x_s=0.026}}$

⛥ Mole fraction of water :

$:\implies\tt\:x_w=\dfrac{n_w}{n_w+n_s}$

$:\implies\tt\:x_w=\dfrac{4.44}{4.44+0.12}$

$:\implies\tt\:x_w=\dfrac{4.44}{4.56}$

$:\implies\boxed{\bf{x_w=0.97}}$