how much pure acid should be mixed with 5 gallons of a 50% acid solution in order to get an 80% acid solution?

Question

how much pure acid should be mixed with 5 gallons of a 50% acid solution in order to get an 80% acid solution?

Answer 1

Using the ideal solution property

   c1 * v1 + c2 * v2 = c * (v1+v2)  - wher c1, c2, c are concentrations and v1, v2 are volumes

 

   Pure acid means concentrations = 100% = 1

   1 *va + 5 * .5 = .8 (va + 5)

     va + 2.5 = .8va + 4

      .2va = 4 -2.5 = 1.5

     va = 1.5 /.2 = 7.5

 

You need 7.5 cgallons of pure acid.