Question

Find the volume of 33.12% hydrochloric acid required to prepare 300.0 g of 12.0 % HCl​?

Answer 1

33.12% HCl acid solution means 33.12 g acid is dissolved in 100 g of solution.

Thus by unitary method,331.2 g acid is dissolved in 1000 g solution.

As here no density of the solution is given we take the density of the solution is 1g/cm³ .

So, 1000 g solution = 1000 ml solution.

Now, in 1000 ml solution acid is dissolved = 331.2 g

So, the molarity of the solution= (331.2/36.5) molar ( as molar weigtht of HCl= 36.5 g mol^-1)

the final solution is 12% HCl i.e 12 gm HCl is dissolved in 100 g solution and similarly 120 HCl is dissolved in 1000 g solution or 120 g HCl is disssolved in 1000 ml solution.

So, the molarity of the final solution = (120/36.5) molar.

if 1000 gm solution= 1000 ml

then 300 gm final solution= 300 ml

So, actually we've to prepare 300 ml (120/36.5) molar solution from (331.2/36.5) molar solution.

let, the volume of the (331.2/36.5) = V ml needed for the final solution.

So, V*(331.2/36.5) = 300*(120/36.5)

V= 108.69 ml

So, to make 300 g 12% HCl solution we need 108.69 ml 33.12% HCl solution.