Percent weight of aspirin in the drug: 42.9%.
So, you know that your drug has a total mass of 0.230 g and that it contains acetylsalicycli acid,
In order to determine exactly how much acetylsalicycli acid your drug contains, you titrate it with sodium hydroxide,
The balanced chemical equation for this reaction looks like this
Notice that you have a
Use the molarity and volume of the potassium hydroxide solution to determine how many moles of base were needed.
This means that the drug contained 0.0005478 moles of acetylsalicyclic acid.
To determine the mass of acetylsalicyclic acid, use its molar mass
The percent composition by weight of aspirin in the drug will be
The answer is rounded to three sig figs, the number of sig figs you gave for the mass of the drug.