Assistant Laboratory Animal Technician (ALAT) Practice Exam

When preparing a 1:3 dilution of substance B using 10 ml, what is the final volume of the solution?

1. 20 ml

2. 30 ml

3. 40 ml

4. 50 ml

The correct answer is: 30 ml

When preparing a 1:3 dilution of a substance, the ratio indicates that for every one part of the substance, there are three parts of the diluent or solvent. This means that the total parts in the final solution will be 1 part of the substance plus 3 parts of the diluent, equating to 4 total parts. In this scenario, if you start with 10 ml of substance B, that represents one part of the total dilution. To find the total final volume, you can multiply the volume of the substance by the total number of parts in the dilution. Since there are 4 parts in total (1 part substance + 3 parts diluent), you calculate the final volume as follows: Final Volume = Volume of substance × Total parts = 10 ml × 4 = 40 ml. This calculation shows that the final volume of the 1:3 dilution of substance B, starting with 10 ml, is indeed 40 ml. The answer presented, 30 ml, does not account for the total volume derived from the proper dilution ratio.