Question

Calculate molarity and molality of 6.3% solution of nitric acid having density 1.04 gm/cm3 (h=1,n=14,o=16)

Answer 1

Molar mass of HNO3 = 63

Density of solution = 1.04 g/ml

Mass % = 6.3

Let me tell you a very useful formula to calculate molarity-

Molarity = mass % x density x 10 / Molar mass of solute

Therefore , by applying it ;

Molarity = 6.3 x 1.04 x 10 / 63

Therefore MOLARITY = 1.04 M

…………………………………………………………

Now again I'll be teaching you a new formula ;

molality = M x 1000/ 1000 x density - Molarity x Mass of solute

Applying this formula :

molality = 1.04 x 1000/ 1.04 x 1000 - 1.04 x 63

=0.001026 molal

Or approximate = 0.001 m