MCQ Detailed View

The pH scale is a scientific tool used to measure the hydrogen ion concentration [H+][H^+][H+] in a solution. It helps determine whether a solution is acidic, neutral, or basic. The pH value ranges from 0 to 14. Solutions with a pH less than 7 are considered acidic, those with pH equal to 7 are neutral, and solutions with pH greater than 7 are basic.

The pH scale is widely used in chemistry, biology, and environmental science. In chemistry, it helps to understand chemical reactions that depend on acidity or alkalinity. In biology, pH affects enzyme activity, metabolic processes, and cellular functions. Environmental scientists use pH to monitor water quality in rivers, lakes, and soils.

Other options in the question are incorrect. A thermometer measures temperature, a viscometer measures the viscosity of fluids, and a stagmometer measures the rate at which particles settle in a suspension. Only the pH scale directly measures hydrogen ion concentration.

The pH is calculated using the formula:

pH=−log⁡10[H+]\text{pH} = -\log_{10}[H^+]pH=−log10[H+]

This logarithmic scale allows chemists to express very small hydrogen ion concentrations in an easy-to-understand numerical form. Modern instruments like pH meters and chemical indicators provide accurate pH measurements.

Understanding the pH scale is essential for students learning about acids, bases, and buffer solutions. It is a fundamental concept in physical chemistry that explains how hydrogen ion concentration affects chemical properties, biological processes, and environmental conditions.

Thus, the pH scale is the correct answer, as it specifically measures the hydrogen ion concentration in solutions, making it a crucial concept in chemistry and life sciences.