Question

Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.5 g per mL and the mass percent of nitric acid in it being 69%.

Answer 1

Mass percent of HNO3=69%

Hence mass of HNO3 in the solution is 69g

Mass of water=100-69=31g

Number of moles of HNO3 =69/63=1.09moles

Density=mass/volume

Volume=mass/density

=100/1.5=66.667 mL

Concentration (Molarity) = number of moles of solute/volume of the solution

= (1.09/66.667)×100

= 1.63M