Solve.
-Chandra has 5 liters of a $56 \%$ solution of sodium hydroxide in a container. What is the amount and concentration of sodium hydroxide solution she must add to this in order to end up with 7 liters of $46 \%$ solution?
A) 2 liters of $19 \%$ solution
B) 2 liters of $21 \%$ solution
C) 2 liters of $24 \%$ solution
D) 2 liters of $22 \%$ solution

Question

Quizplus · Accepted Answer

To solve this, we can use the equation for the concentration of the final solution. Initially, Chandra has 5 liters of a 56% solution, which means she has $5 \times 0.56 = 2.8$ liters of pure sodium hydroxide. She wants to end up with 7 liters of a 46% solution, which means she needs $7 \times 0.46 = 3.22$ liters of pure sodium hydroxide in total. Therefore, she needs to add $3.22 - 2.8 = 0.42$ liters of pure sodium hydroxide. If she is adding 2 liters of solution to reach 7 liters, the concentration of the solution she needs to add can be found by dividing the amount of pure sodium hydroxide she needs to add by the volume of solution she is adding: $0.42 \div 2 = 0.21$ or 21%. Therefore, she needs to add 2 liters of a 21% sodium hydroxide solution.

Solve -Chandra Has 5 Liters of A 56 56%56 \%56% Solution of Sodium Hydroxide in a Container

Solve
-Chandra Has 5 Liters of A 56 $56 \%$ Solution of Sodium Hydroxide in a Container