Question

This is an extraction problem:where K=C2/C1

calculate the volume in milliiliters of a organic solvent that must be used to remove 60 % of a compound present in 100mL of an aqueous solution with only one extraction? given K (org solvent/water)= 3.0

Answer 1

Let the weight of the compound present in 100 ml of water be ' w ' gms.

so, concentration of compound in aqueous layer ................= w / 100   

therefore , wt. of compound in organic layer afte extraction = 0.6w gms

let volume in mililitres of organic solvent be........................= v ml.

so, concentration of compound in organic layer ..................= 0.60 / v

Now ; concentration of compound in organic solvent / concentration of compound in water = K

ie. .............................................................................................( 0.60 w / v) / (w / 100 ) = 3.0

.............................................................................................................................& v = 20.0 ml.

Thus the volume of organic solvent that must be used to remove 60 % of a compound........ = 20.0ml

.