Engineering Board Exam Reviewer · Mixture Problems · medium
A chemist has a 40% acid solution and a 70% acid solution. How many liters of the 70% solution must be added to 10 L of the 40% solution to make a 50% solution?
- 2.5 L
- 10 L
- 5 L
- 15 L
Answer
C. 5 L
Solution
Acid balance: 0.40(10)+0.70x=0.50(10+x) 4+0.7x=5+0.5x 0.2x=1 x=5 L.
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