A chemist mixes x mL of a 34% acid solution with a 10% acid solution. If the resulting solution is 40 mL with 25% acidity, what is the value of x?

Explanation

To solve the question, we apply the concept of mixtures and percentages. We define x as the volume of the 34% acid solution in mL. The amount of acid in the 34% solution is given by 0.34x mL, while the amount of acid in the 10% solution is 0.1(40 - x) mL, since the total volume of the solution is 40 mL.The total amount of acid in the resulting solution is 25% of 40 mL, which is 10 mL. To find x, we set up the equation:0.34x + 0.1(40 - x) = 10Solving this equation, we simplify:0.34x + 4 - 0.1x = 100.24x = 6x = 25This calculation shows that the correct amount of the 34% acid solution needed is 25 mL, making option D the correct answer. Other options fail to satisfy the equation and do not yield the correct final acidity percentage.