Question

Which Limnological parameter indicates the level of acidity or alkalinity of water?

• A. Turbidity
• B. Total dissolved solids
• C. pH
• D. Biochemical oxygen demand (BOD)

Hint:

The term "pH" stands for "potential of Hydrogen," which is the standard scale for measuring acidity and alkalinity.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Acidity and alkalinity are defined by the balance of hydrogen ions (H$^+$) and hydroxyl ions (OH$^-$) in an aqueous solution.
Key Formula or Approach:
The pH scale is a logarithmic scale defined as:
\[ \text{pH} = -\log_{10}[\text{H}^+] \]

Step 2: Detailed Explanation:
A pH of $7$ indicates neutral water, where the concentration of hydrogen ions equals the concentration of hydroxyl ions.
A pH below $7$ indicates acidic conditions, characterized by an excess of hydrogen ions.
A pH above $7$ indicates alkaline or basic conditions, characterized by an excess of hydroxyl ions.
Limnological parameters like turbidity measure water clarity, total dissolved solids (TDS) measure dissolved inorganic salts, and BOD measures organic load, leaving pH as the indicator of acidity/alkalinity.

Step 3: Final Answer:
Therefore, pH is the limnological parameter that indicates whether water is acidic, neutral, or alkaline.