Table of Contents
Alligation alternate is a useful mathematical method used in pharmacy and medicine to prepare a mixture of solutions with different concentrations. It helps in calculating the proportions of different drug solutions needed to achieve a desired concentration in the final mixture. This article provides practice problems to enhance understanding of alligation alternate in the context of drug solutions.
Understanding Alligation Alternate
Alligation alternate involves arranging the different concentrations of solutions and calculating the ratios in which they should be mixed. It is especially helpful when dealing with solutions of varying strengths to produce a solution of a specific concentration.
Key Concepts
- Mean concentration: The desired concentration of the final mixture.
- Component solutions: The available solutions with different concentrations.
- Alligation method: A step-by-step process to determine the ratio of component solutions.
Practice Problems
Problem 1
How much of a 10% drug solution and a 20% drug solution are mixed to prepare 100 ml of a 15% solution?
Solution
Using alligation alternate:
Difference between the higher concentration (20%) and the desired concentration (15%) is 5.
Difference between the desired concentration (15%) and the lower concentration (10%) is 5.
Ratio of 10% to 20% solution = 5:5, which simplifies to 1:1.
Total parts = 1 + 1 = 2.
Amount of 10% solution = (1/2) × 100 ml = 50 ml.
Amount of 20% solution = (1/2) × 100 ml = 50 ml.
Answer: Mix 50 ml of 10% solution with 50 ml of 20% solution.
Problem 2
How much of 5% and 15% solutions are needed to prepare 200 ml of a 10% solution?
Solution
Difference between the higher concentration (15%) and the desired concentration (10%) is 5.
Difference between the desired concentration (10%) and the lower concentration (5%) is 5.
Ratio of 5% to 15% solution = 5:5, which simplifies to 1:1.
Total parts = 2.
Amount of 5% solution = (1/2) × 200 ml = 100 ml.
Amount of 15% solution = (1/2) × 200 ml = 100 ml.
Answer: Mix 100 ml of 5% solution with 100 ml of 15% solution.
Additional Practice
Students are encouraged to try more problems with different concentrations and volumes to master the alligation alternate technique. Remember to always verify your calculations and understand the ratios involved.