How many grams of concentrated nitric acid solution should be used to prepare 250mL of 2.0M `HNO_(3)` ? The concentrated acid is 70% `HNO_(3)` (w/w)

Options

A. 90g conc. `HNO_(3)`
B. 70g conc. `HNO_(3)`
C. 54g conc. `HNO_(3)`
D. 45 g conc. `HNO_(3)`

Answer

D

Explanation

Molarity (M) `=(w_(B) xx 1000)/(mol wt. xx "vol (ml)")`
`2 = (w_(B))/(63) xx (1000)/(250)`
mass of `HNO_(3)` in 250ml 2M solution =31.5g
Wt of 70% acid `=(100)/(70) xx 31.5= 45g`