Question

Calculate the concentration of nitric acid in moles per litre in a sample which has a density `1.41 g mL^(-1)` and the mass percent of nitric acid in it being `69%`.

Answer 1

Mass persent of nitric acid in the sample =69% [Given ]
Thus ,100 g of nitric acid contains 69 g of nitric acid by mass .
molar mass of nitric acid `(HCO_(3))`
`={1+14+3(16)} g mol ^(-1)`
=1+14+48
`=63 g mol ^(-1)`
`therefore` Number of moles in 69 g of ` HNO _(3)`
`=(69 g)/(63 g mol^(-1))`
=1.095 mol
Volume of 100 g of nitric acid solution
`=("Mass of solution")/("density of solution ")`
`=(100 g)/(1.41 g mL^(-1))`
`=70.92 mL -= 70.92 xx 10^(-3) L`
Concentration of nitric acid
`=(1.095"mole")/(70.92xx10^(-3)L)`
=15.44 mol/ L
`therefore` Concentration of nitric acid = 15.4 mol/L