1. What is Alligation Method?

The alligation method is a mathematical technique used to calculate the proportion of different ingredients needed to create a mixture of desired strength from ingredients of different concentrations.

2. How Alligation Calculation Works

The alligation method uses the following approach:

Where:

• High Concentration - The stronger component
• Low Concentration - The weaker component (can be zero)
• Desired Concentration - The target concentration
• Parts - Dimensionless quantities representing proportions

Explanation: The difference between desired and low gives parts of high concentration, and the difference between high and desired gives parts of low concentration.

3. Practical Applications

Details: Alligation is commonly used in pharmacy for preparing solutions of specific concentrations, in chemistry for preparing reagents, and in various manufacturing processes.

4. Using the Calculator

Tips: Enter the concentrations of your high and low strength components, along with your desired concentration. All values must be positive numbers with high > low.

5. Practice Questions

Q1: How would you prepare 500mL of a 15% solution using 20% and 10% solutions?
A1: High parts = 15-10 = 5, Low parts = 20-15 = 5. Ratio 1:1. So 250mL of each.

Q2: What ratio of 95% alcohol and water should be mixed to prepare 70% alcohol?
A2: High parts = 70-0 = 70, Low parts = 95-70 = 25. Ratio 70:25 or 14:5.

Q3: How much 50% dextrose and 5% dextrose are needed to make 1L of 10% dextrose?
A3: High parts = 10-5 = 5, Low parts = 50-10 = 40. Total parts = 45. (5/45)×1000 = 111mL of 50%, (40/45)×1000 = 889mL of 5%.

Q4: What's the ratio for mixing 30% solution with pure solvent to get 12% solution?
A4: High parts = 12-0 = 12, Low parts = 30-12 = 18. Ratio 12:18 or 2:3.

Q5: How to prepare 300g of 8% ointment using 10% and 3% ointments?
A5: High parts = 8-3 = 5, Low parts = 10-8 = 2. Total parts = 7. (5/7)×300 = 214g of 3%, (2/7)×300 = 86g of 10%.