Final answer:
The new concentration of the solution after dilution to 750 ml is 4%, which is the percent strength that should be labeled on the solution.
Step-by-step explanation:
The student has been given 300 ml of a 10% solution and needs to dilute it to 750 ml. To find the new concentration, we have to use the concept of dilution which is based on the principle that the amount of solute remains constant before and after the dilution process. In this case, the initial amount of solute is 300 ml × 10% = 30 ml. After diluting to 750 ml, the percent strength of the solution can be calculated using the formula:
percent strength = (volume of solute / volume of solution) × 100
percent strength = (30 ml / 750 ml) × 100
percent strength = 4%
Therefore, the label on the diluted solution should indicate a 4% strength.