Q. 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) 45.0 g conc. HNO₃
B) 90.0 g conc. HNO₃
C) 70.0 g conc. HNO₃
D) 54.0 g conc. HNO₃
Explanation
[Solution from source] Moles of HNO₃ = 2.0 × 0.250 = 0.50 mol = 0.50 × 63 = 31.5 g. The 70% solution needed = 31.5/0.70 = 45.0 g. 90 g comes from doubling the moles. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.