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 percent of nitric acid in it being 69%.

Answer 1

69 mass percent of nitric acid means that 69 g of HNO₃ are present in 100 g of solution. 

Volume of solution = Mass/Density = 100g/1.41mL⁻¹ = 70.92 mL 

Moles of HNO₃ = 69/63 = 1.095 

Therefore Molarity = Moles of HNO₃ /Volume of solution (in ml ) x 1000 = 1.095/70.92 x 1000 = 15.44 M