Answer:
The chemist must drain 78 g of 25% acid solution and replace with 78 g of 70% acid.
Step-by-step explanation:
- x= mass of the 25% acid the chemist must drain,
- Then we have,
- x= the mass, m of the 70% acid,
- 100-x=the mass of the 25% acid remaining,
- The operating equation is,
- Mass of acid in 25% + Mass of acid in 70%= Mass of acid in 60%,
- 0.25(100-x)+0.70 x=0.60×100,
- 25 - 0.25 x 0.70 x=60,
- 0.45 x= 35,
- x= 35/0.45,
- so we get,
- x=78 g.
