Question

100 cm³ of a centimolar solution of an acid contain 0.098 g of the acid. Find the molecular mass of the acid.

Answer 1

Given: Mass % of HNO₃ = 69%

Mass of pure HNO₃ = 23 g

Density of the solution = 1.41 g/cm³

We are to calculate the volume of solution (in cm³) that contains 23 g of HNO₃.

Let volume of the solution be V cm³

Then,

Mass of solution = Density × Volume

= 1.41 × V

Since 69% of the mass is HNO₃

Mass of HNO₃ = 69% of 1.41 V

Set this equal to 23 g

0.9729 × V = 23

V = `23/0.9729`

V = 23.64 cm³