# Equivalent Weight Calculation using Double Decomposition Method

You can easily calculate the equivalent weight of a chemical compound with the double decomposition method. This user-friendly tool takes the weight of two compounds, the equivalent mass of one compound. Press the calculate button to avail the equivalent weight of the second compound.

### Calculation of Equivalent Weight using Double Decomposition Method

The number of substances that completely react with each other in the reaction is called equivalent weight.

The format of a double decomposition reaction is along the lines:

**AB + CD → CB + AD**

The double decomposition reaction is used to find the equivalent weight of the compounds.

The formula to find equivalent weight using double decomposition is

**EW₂=(EW₁*weight of CB/weight of AB)**.

Where,

EW₁ is the equivalent weight of AB

EW₂ is the equivalent weight of CB

### How to Find Equivalent Weight with Double Decomposition Method?

- Check the weight of the reactant AB, and product CB.
- Get the equivalent weight of AB.
- Multiply the known equivalent weight by the weight of BC.
- Divide the product by the weight of AB to obtain the unknown equivalent weight.

**Example:**

Calculate the equivalent weight of CB through the double decomposition method. If the weight of AB is 25, the weight of CB is 30, and an equivalent weight of AB is 15.

**Solution:**

Given that,

Weight of AB = 25

Weight of CB = 30

Equivalent weight of AB (EW₁) = 15

Equivalent weight of CB EW₂=(EW₁*weight of CB/weight of AB).

= (15 * 30/25)

= 50

### FAQ's on Equivalent Weight Calculation using Double Decomposition Method

**1. How is equivalent weight calculated?**

The equivalent weight of a substance can be calculated by substituting the values in the formula Equivalent Weight = Molecular Weight/Valency.

**2. What is a double decomposition reaction?**

A double decomposition reaction is a type of decomposition reaction in which two constituent reactants exchange positive, and negative ions to form two new compounds. Example is CaCl_{2} + (NH_{4})_{2} CO_{3} → CaCO_{3} + NH_{4}Cl.

**3. Why do we use equivalent weight?**

Equivalent weight is used to calculate the normality. The normality is the number of gram equivalents of solute in a litre of the solution.

**4. What is the Equivalent Mass Formula using Double Decomposition Method?**

The equivalent weight using the double decomposition method formula is EW₂=(EW₁*weight of CB/weight of AB).