Final answer:
The percent strength of an Antihistamine 12.5 mg/5 mL elixir is calculated as 0.25% by converting the medication amount to grams per 100 mL of solution. The options provided in the question contain an error as none of them accurately represent the calculated percent strength.
Step-by-step explanation:
The student has asked about the percent strength of a medication in an Antihistamine 12.5 mg/5 mL elixir. The percent strength is calculated by the amount of the active ingredient in a specific amount of solution. In this case, we have 12.5 mg of medication in 5 mL of elixir. To find the percent strength, we need to determine how much medication would be in 100 mL of elixir, as percent strength is typically given in terms of a 100 mL solution.
If 5 mL contains 12.5 mg, then 100 mL would contain (12.5 mg / 5 mL) * 100 mL = 250 mg. Now, we express this amount in grams because percent strength is based on grams per 100 mL. Since 1000 mg is equivalent to 1 g, 250 mg is 0.25 g. Therefore, the percent strength is (0.25 g / 100 mL) * 100 = 0.25%, which isn't an option provided.
However, this seems to be an error in the available options, as the correct answer calculated here does not match any of the choices. The closest match would be option A (2.5%), although that is numerically incorrect.