Question 70

The final percentage strength of the drug is 6.67%.

When 500 mL of a 20% (v/v) solution is diluted to a total volume of 1500 mL, the final concentration can be calculated using the dilution formula, which results in a strength of 6.67%.

A) 1.77%

This option is incorrect because it significantly underestimates the dilution effect. Diluting 500 mL of a 20% solution to 1500 mL cannot yield such a low concentration, as the volume increase would not reduce the strength to this extent.

B) 3.23%

This option is also incorrect. A 3.23% concentration does not accurately reflect the dilution of a 20% solution to 1500 mL. The calculation shows that the concentration remains higher than this percentage after dilution.

C) 6.67%

This is the correct answer. When the 20% solution is diluted from 500 mL to 1500 mL, the concentration is reduced proportionally, resulting in a final strength of 6.67%. This is calculated by the formula: (Volume of solute / Total volume) x 100.

D) 8.95%

This option is incorrect as it overestimates the final concentration. The dilution process of a 20% solution to 1500 mL achieves a final strength of 6.67%, which is lower than 8.95%, demonstrating a misunderstanding of how dilution affects concentration.

Conclusion

The correct answer, 6.67%, accurately represents the final concentration after diluting a 20% solution from 500 mL to 1500 mL. The other options fail either by underestimating or overestimating the dilution effect, confirming that they do not align with the calculated outcome of the dilution process.