Concentration of Solution: Types, Formulas, and Easy Examples for Class 12

Understanding the Concentration of Solution is a fundamental concept in chemistry, crucial for mastering both theoretical knowledge and practical applications. Whether you’re preparing for competitive exams or aiming to score well in your Class 12 chemistry, a clear grasp of this topic can make a significant difference. In this guide, we’ll break down the different types of solution concentrations, essential formulas, and provide easy-to-follow examples to simplify your learning. Let’s dive into this important topic and make it easier than ever to understand!

What is the Concentration of a Solution?

The concentration of a solution refers to the amount of solute present in a given quantity of solvent or solution. It helps measure how “strong” or “diluted” a solution is.

For example:

• A highly concentrated solution contains more solute and less solvent.
• A dilute solution has more solvent and less solute.

Understanding concentration is crucial in:

• Laboratory experiments
• Industrial chemical processes
• Daily activities like preparing a sugar solution

Types of Concentration of Solution

Let’s understand the common types of solution concentrations with formulas and examples.

Mass Percentage (w/w)

The percentage of the mass of solute in the total mass of the solution.

Formula:

$$\text{Mass %} = \frac{\text{Mass of Solute}}{\text{Mass of Solution}} \times 100$$

Example:
If 10 g of salt is dissolved in 90 g of water, the mass percentage is:

$$\text{Mass %} = \frac{10}{10 + 90} \times 100 = 10$$

Volume Percentage (v/v)

Definition: The volume of solute per 100 mL of solution.

Formula:

$$\text{Volume \%} = \frac{\text{Volume of Solute}}{\text{Volume of Solution}} \times 100$$

Example:
Mixing 25 mL of alcohol with 75 mL of water gives:

$$\text{Volume \%} = \frac{25}{100} \times 100 = 25\%$$

Mass by Volume Percentage (w/v)

Definition: The mass of solute in grams per 100 mL of solution.

Formula:

$$\text{Mass by Volume \%} = \frac{\text{Mass of Solute}}{\text{Volume of Solution}} \times 100$$

Example:
Dissolving 5 g of sugar in 100 mL of water gives:

$$\text{Mass by Volume \%}=\frac{5}{100}\times 100=5\mathrm{\%}$$ $$\text{Mass by Volume \%} = \frac{5}{100} \times 100 = 5\%$$

Molarity (M)

Definition: The number of moles of solute dissolved in one liter of solution.

Formula:

$$\text{Molarity} = \frac{\text{Moles of Solute}}{\text{Volume of Solution (in liters)}}$$

Example:
If 0.5 moles of NaCl are dissolved in 2 L of water:

$$M=\frac{0.5}{2}=0.25\text{M}$$

Molality (m)

Definition: The number of moles of solute per kilogram of solvent.

Formula:

$$\text{Molality} = \frac{\text{Moles of Solute}}{\text{Mass of Solvent (in kg)}}$$

​Example:
If 1 mole of glucose is dissolved in 0.5 kg of water:

$$m=\frac{1}{0.5}=2\text{m}$$

Normality (N)

Definition: The number of gram equivalents of solute per liter of solution.

Formula:

$$\text{Normality} = \frac{\text{Gram Equivalents of Solute}}{\text{Volume of Solution (in liters)}}$$

Mole Fraction (X)

Definition: The ratio of the moles of one component to the total moles in the solution.

Formula:

$$X = \frac{\text{Moles of Solute}}{\text{Moles of Solute + Moles of Solvent}}$$

Key Formulas for Concentration of Solution

Below is a table summarizing the key formulas: