Concept of pH

Concept of pH and Its Use to Determine the Nature of a Solution

What is pH?

The term pH stands for "potential of hydrogen." It is a scale used to measure how acidic or basic (alkaline) a solution is. The pH value tells us the concentration of hydrogen ions (H⁺) present in the solution.

The pH scale is numbered from 0 to 14 and is used to indicate the acidity or basicity of a solution:

• pH below 7: Indicates an acidic solution
• pH equal to 7: Neutral solution
• pH greater than 7: Basic (alkaline) solution

How is pH Measured?

We can find out the pH of a solution by using the following methods:

• pH paper or litmus paper: It changes color based on the solution's pH.
• pH meter: An electronic device that gives a precise pH reading.
• Universal indicator: A solution that shows different colors for different pH values.

Use of pH to Determine Nature of Solution

Measuring the pH of a solution helps determine if it is acidic, basic, or neutral. Here's how it works:

• If the pH is between 0 and 6.9, the solution is acidic.
• When the pH value is 7, the solution is considered neutral, such as in the case of pure water.
• If the pH is between 7.1 and 14, the solution is basic or alkaline.

Examples:

• Lemon juice – pH around 2 (acidic)
• Soap solution – has a pH close to 9, indicating it is basic in nature
• Distilled water – has a pH of 7, meaning it is neutral

Importance of pH in Daily Life

• Soil pH affects plant growth.
• Our stomach contains hydrochloric acid with low pH for digestion.
• Shampoos and skincare products are pH-balanced for safe use.

The idea of pH allows us to identify if a substance is acidic, neutral, or alkaline in nature. This is useful in chemistry, health, agriculture, and many other areas of life.