Question

Aqueous solution of urea is 20% by mass of solution then the percentage by mass of solvent is

Answer 1

Let the mass of the solution be 100gm.

Hence, mass of urea = 20/100 * 100

                                   = 20gm

Hence, mass of water= 100 - 20 = 80gm

Now, percentage by mass of solvent(urea) = 20/80 * 100

= 25% answer