In what ratio should a 15% solution of acetic acid be mixed with a 3% solution of the acid to prepare a 10% solution (all percentage are mass/mass percentage) :

Options

A. `7:3`
B. `5:7`
C. `7:5`
D. `7:10`

Answer

C

Explanation

`(15/60xx1000/100V_1+3/60xx1000/100V_2)/(V_1+V_2)=10/60xx1000/100`
or `1/4V_1+1/20V_2=1/6(V_1+V_2)` or `V_1/4-V_1/6=V_2/6-V_2/20`
or `(6V_1-4V_1)/24=(10V_2-3V_2)/60` or `(2V_1)/24=(7V_2)/60` or `V_1/V_2=7//5`