Question

concentrated aqueous nitric acid is 69% hno3 my mass and has density of 1.41gml^-1. volume of acid required to make one litre of 0.2M hno3 is

Answer 1

Given info : The concentration of aqueous solution of nitric acid (HNO₃) is 69 % by mass and has density of 1.41 g/ml.

To find : the volume of water required to make of 0.2 M, HNO₃ , is...

solution : concentration of HNO₃ is 69 % by mass. means 69g of HNO₃ is present in 100g of solution.

molecular weight of HNO₃ = 63g/mol

∴ no of moles of HNO₃ = given mass/molar mass = 69/63 = 1.095 mol

mass of solution = 100g

and density of solution = 1.41g/ml

so volume of solution = 100/1.41 = 70.92 ml

now molarity of solution = mole of HNO₃/volume of solution in L

= 1.095/(70.92/1000)

= 15.44 M , this is concentration of acid

let v volume of water required to make 0.2 M HNO₃.

now, initial no of moles of HNO₃ = final no of moles of HNO₃ [ from dilution concept ]

⇒1.095 mol = 0.2 mol/L× (70.92/1000 L + v)

⇒5.475 - 0.07092 = v

⇒v = 5.4048 L ≈ 5.4 L

Therefore 5.4 L of water required to make 0.2 M HNO₃