This question belongs to physical chem- SOLUTIONS.

How many grams of conc. nitric acid solution should be used to prepare 250ml of 2.0 M HNO3?

1. 54.0 conc. HNO3
2. 45.0 conc. HNO3
3. 90.0 conc. HNO3
4. 70.0 conc. HNO3

The required number of moles=( 250/1000)×2
=0.5 moles
(no. of moles=molarity × volume)
so,required mass of HNO₃=0.5×63
=31.5 grams
(given mass=no. of moles × molar mass)
Given, 
70 grams of HNO3 are present in 100 grams of the solution
so,1 gram will be present in 100/70 grams of solution
hence 31.5 grams will be present in (100/70)×31.5 grams of solution.
so amount of concentrated nitric acid solution used is 45 grams.