Question

How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO₃? The concentrated acid is 70% HNO₃.

(a) 70.0 g conc. HNO₃

(b) 54.0 g conc. HNO₃

(c) 45.0 g conc. HNO₃

(d) 90.0 g conc. HNO₃

Answer 1

Correct option (c) 45.0 g conc. HNO₃

Explanation :

Answer 2

Option C is correct

Molar mass of HNO3= 63g/mol

100 g 70% HNO3 contains 70g or 70/63 mole HNO3

So xg will contain 0.7/63*x=0.1*x /9 mol HHO3

If this x g conc Solution is required to make 250 mL 2M solution then

So 0.1 x*/9= 250×2/1000

=>x=45 g