Question

Which of the following procedures correctly outlines the steps for preparing a serial dilution of a methylene blue stock solution?

a. Start with the most diluted solution and sequentially add water until reaching the stock concentration.
b. Begin with the stock solution and add equal volumes of water in each step.
c. Dilute the stock solution by adding water first, then gradually increase the concentration in subsequent steps.
d. Combine equal volumes of different concentrations to create a serial dilution.
e. Prepare the serial dilution by adding equal amounts of methylene blue to different volumes of water.

Answer 1

The correct method for preparing a serial dilution is to start with a stock solution and dilute it stepwise with equal volumes of water.

Step-by-step explanation:

The correct procedure for preparing a serial dilution of a methylene blue stock solution is to begin with the stock solution and sequentially add water in each step to achieve progressively more dilute solutions. The correct option from the ones provided is: b. Begin with the stock solution and add equal volumes of water in each step. This approach keeps the process consistent and allows for the calculation of the concentration in each step using the known concentration of the stock solution. Preparation of a serial dilution often involves measuring a specified volume of the stock solution and diluting it with a solvent, usually water, to a certain final volume, utilizing the concept that the number of moles remains constant during the dilution process, as shown in various steps of solution preparation.