What is the scale for measuring a hydrogen ion concentration in a solution?

Correct option is A

Ans. (a) pH scale

Sol. The pH scale is used to measure the concentration of hydrogen ions (H⁺) in a solution. It ranges from 0 to 14, where values below 7 indicate acidity, 7 is neutral, and above 7 indicate alkalinity. The pH scale is logarithmic, meaning each unit change represents a tenfold difference in H⁺ concentration. It is widely used in chemistry, biology, medicine, and industry to determine the chemical nature of substances.

Information Booster:

• The term pH stands for "potential of hydrogen" or "power of hydrogen."
• The pH is calculated using the formula: pH=−log⁡10[H+]pH = -\log_{10} [H^+]pH=−log⁡10[H+]pH = -\log_{10} [H^+]pH=−log10​[H+]​
• The human body maintains a blood pH of 7.35–7.45, which is essential for survival.
• Acids have a pH below 7 (e.g., lemon juice has a pH of ~2), while bases have a pH above 7 (e.g., bleach has a pH of ~12).
• pH indicators like litmus paper, universal indicators, and electronic pH meters are used for measurement.
• The pH of seawater is around 8.1, but ocean acidification is lowering it due to increased CO₂ absorption.
• pH control is crucial in agriculture, medicine, water treatment, and food processing industries.

Additional Information:

• OH Scale (b) – Incorrect: There is no separate "OH scale." Instead, pOH measures hydroxide ion (OH⁻) concentration, and it relates to pH as:$$pH+pOH=14$$
• Hydrogen Scale (c) – Incorrect: This term is not a recognized scientific measurement. The pH scale is the standard for measuring hydrogen ion concentration.
• dB Scale (d) – Incorrect: The decibel (dB) scale measures sound intensity, signal strength, or power ratios, not acidity or alkalinity.