What is the percentage strength of a solution that contains 7.5 grams of drug in 250ml?

To determine the percentage strength of a solution, the formula used is:

[

\text{Percentage Strength} = \left( \frac{\text{grams of solute}}{\text{volume of solution in mL}} \right) \times 100

]

In this scenario, we have 7.5 grams of drug in a 250 mL solution. Plugging the values into the formula gives:

[

\text{Percentage Strength} = \left( \frac{7.5 \text{ grams}}{250 \text{ mL}} \right) \times 100

]

Calculating this step-by-step:

1. Divide the amount of drug by the volume of the solution:

[

\frac{7.5}{250} = 0.03

]

2. To convert this fraction to a percentage, multiply by 100:

[

0.03 \times 100 = 3

]

Thus, the percentage strength of the solution is 3%. This calculation accurately reflects the concentration of the drug in the solution, leading to the conclusion that the correct answer is indeed 3.