Question

How many grams of concentrated nitric acid solution should be used to prepare `250 mL` of `2.0 M HNO_(3)`? The concentrated acid is `70% HNO_(3)`:
A. `45.0" g conc. HNO"_(3)`
B. `90.0" g conc. HNO"_(3)`
C. `70.0" conc. HNO"_(3)`
D. `54.0" g conc. HNO"_(3)`

Answer 1

Correct Answer - A
`(w)/(E)=NV`
`(w)/(6.3)=2xx(250)/(1000)`
`w=(63)/(2)=31.5g`
but `70%` solution
70 g is used the wt. of solution is 100 g
31.5 g is used the wt. of solution is ?
`(100)/(70)xx31.5=45g`