How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3?

The number of moles of nitric acid can be obtained by multiplying the molarity with volume
M × V = Moles of HNO3 = 250 × 2 / 1000 = 0.5
The molar mass of HNO3 is 63 g/mol.
Mass of HNO3 = moles × molar mass = 0.5 mol × 63 g/mol = 31.5 g
Assuming the concentrated nitric acid solution is 70% HNO3 by mass, then:
Mass of concentrated HNO3 solution = (Mass of HNO3) / (Percentage of HNO3) × 100%
Mass of concentrated HNO3 solution = 31.5 g / 70% × 100% = 45 g
Therefore, 45.0 g of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3.