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)`:

Options

A. `45.0g" conc".HNO_(3)`
B. `90.0g" conc".HNO_(3)`
C. `70.0g" conc".HNO_(3)`
D. `54.0g" conc".HNO_(3)`

Answer

A

Explanation

Volume of solution `=250mL=(1)/(4)L`
`"Molar mass of "HNO_(3)=63g " mol"^(-1)`
`:."Weight of "HNO_(3)="molarity"xx"mol.mass"xx"volume"(L)`
`=2xx63xx(1)/(4)g=31.5g`
It is the weight of `100%HNO_(3)`.
But the given acid is `70%HNO_(3)`.
`:."Its weight"=31.5xx(100)/(70)g=45g`