What is the pH of 0.4 M HCl?

Learn about the pH of 0.4 M HCl solution, its significance, and real-life applications. Discover the calculation formula and its importance in various fields.

Understanding pH and Its Significance

pH is a measure of acidity or basicity of a solution on a scale of 0 to 14, with 0 being highly acidic, 7 neutral, and 14 highly basic. It is crucial in various fields such as chemistry, biology, and environmental science.

Calculating the pH of 0.4 M HCl

Hydrochloric acid (HCl) is a strong acid that dissociates completely in water. When a 0.4 M solution of HCl is made, it results in a concentration of 0.4 moles of HCl per liter of solution. Since HCl is a strong acid, it donates all its protons in a reaction, making it highly acidic.

The pH of a 0.4 M HCl solution can be calculated using the formula: pH = -log[H+]. Substituting the concentration of HCl into the equation gives us: pH = -log(0.4) = 0.4. Therefore, the pH of a 0.4 M HCl solution is 0.4.

Significance of pH in Real-life Applications

pH plays a crucial role in various real-life applications. For example, in the field of medicine, knowing the pH of a solution is essential for determining the effectiveness of drugs. In agriculture, pH levels of soil impact plant growth and crop yields. Understanding pH is also vital in water treatment processes to maintain safe drinking water standards.


The pH of a 0.4 M HCl solution is 0.4, indicating its highly acidic nature. Understanding pH and its significance in different fields is essential for making informed decisions and solving complex problems.

Leave a Reply

Your email address will not be published. Required fields are marked *