Question

Nitric acid is 68% by weight and density of solution is 1.504 g/ml

Calculate Molarity

Answer 1

Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in an aqueous solution. This means that 68 g of nitric acid is dissolved in 100 g of the solution.

Molar mass of nitric acid (HNO₃) = 1 × 1 + 1 × 14 + 3 × 16 = 63 g mol ^{- 1}

Then, number of moles of HNO₃ = 68 / 63 mol

= 1.08 mol

Also density = 1.504g/mL^-1 (given)

Therefore from the formula density = mass / volume,we get

Volume of solution = 1000/1.504 = 66.49 mL

Therefore molarity of nitric acid = (1.08/66.49) x 1000 = 16.24 M