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

1. (1) 54.0 conc. HNO₃
2. (2) 45.0 conc. HNO₃
3. (3) 90.0 conc. HNO₃
4. (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.

 

Regards

Arun (askIITians forum expert)