Question

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%

Answer 1

Answer:

Concentration of HNO3 = 15.44 mol/L

Explanation:

Mass Percent of HNO3 given in the Sample = 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}

No. of moles in 69 g of HNO3:

=  69g/63g

= 1.095 moles

 

Volume of 100g HNO3 solution:

=Mass/ Density  

= 100g/1.41 g ml^-1= 70.92 ml=70.92× 10^-3L

Molarity(mol/l)

=1.095mol/70.92×10^-3 L

= 15.44mol/L

Therefore, Concentration of HNO3 = 15.44 mol/L

Hope it helps :)