Answer to Question #308884 in Electricity and Magnetism for Junard

Question

What are the mole fractions of hydrochloric acid (HCI) and water in a 20% (w/w) aqeous HCl solution?

Answer 1

mass of H₂O =100gm-20gm=80gm

Mass of H₂O=80gm

Now

$\frac{20gm\times1mol hcl}{36.46gm}=0.5485Hcl$

Now

$\frac{80gm\times1mol hcl}{18.015g}=4.4407molH_2o$

$\chi_{hcl}=\frac{mol hcl}{total mol}$

$\chi_{hcl}=\frac{0.5585}{0.548+4.4407}=0.1$

$$\chi_{H_2o}=(1-\chi_{Hcl})=(1-0.1)=0.9$$