Dilution Formula

The Formula

M_1V_1 = M_2V_2 (molarity × volume before = molarity × volume after)

When to use: Watering down a drink—same amount of flavor, more liquid, weaker taste.

Quick Example

Dilute 100 mL of 2M HCl with water to 200 mL total → resulting concentration is 1M.

What This Formula Means

The process of adding more solvent to a solution in order to lower its concentration.

Watering down a drink—same amount of flavor, more liquid, weaker taste.

Worked Examples

Example 1

easy
How much water must be added to 100\,\text{mL} of 6.0\,\text{M HCl} to make a 1.0\,\text{M} solution?

Solution

  1. 1
    Use M_1V_1 = M_2V_2: 6.0 \times 100 = 1.0 \times V_2.
  2. 2
    V_2 = 600\,\text{mL}.
  3. 3
    Water to add = 600 - 100 = 500\,\text{mL}.

Answer

500\,\text{mL of water}
Dilution does not change the number of moles of solute — it only increases the total volume. The dilution equation M_1V_1 = M_2V_2 reflects this conservation.

Example 2

medium
A stock solution of \text{H}_2\text{SO}_4 is 12.0\,\text{M}. What volume is needed to prepare 500\,\text{mL} of 0.60\,\text{M} solution?

Why This Formula Matters

How lab solutions of specific concentrations are prepared from concentrated stock solutions.

Frequently Asked Questions

What is the Dilution formula?

The process of adding more solvent to a solution in order to lower its concentration.

How do you use the Dilution formula?

Watering down a drink—same amount of flavor, more liquid, weaker taste.

Why is the Dilution formula important in Chemistry?

How lab solutions of specific concentrations are prepared from concentrated stock solutions.

What do students get wrong about Dilution?

Always add acid to water when diluting, never water to acid — the heat released can cause dangerous splashing.

What should I learn before the Dilution formula?

Before studying the Dilution formula, you should understand: concentration.

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Related Concepts

ConcentrationTitration