Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the mass per cent of nitric acid in it being 69%
Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the mass per cent of nitric acid in it being 69%

Mass percent of HNO3 in sample is 69 %

Thus, 100 g of HNO3 contains 69 g of HNO3 by mass.

Molar mass of HNO3

= { 1 + 14 + 3(16)} g.mol^{-1}

= 1 + 14 + 48

= 63g mol^{-1}

 

Now, No. of moles in 69 g of HNO3

= {69\:g}/{63 gmol^{-1}}

= 1.095 mol

 

Volume of 100g HNO3 solution

=\frac{Mass\ of\ solution}{density\ of\ solution}

= 70.92mL

70.92 X10^{-3}\;L

Concentration of HNO3

=\frac{1.095\;mole}{70.92\times {{10}^{-3}}L}

= 15.44mol/L

Concentration of HNO3 = 15.44 mol/L