Which of the following ions functions to maintain osmotic pressure and pH balance in biological systems?

• A. Potassium ion (K+)
• B. Sodium ion (Na+)
• C. Calcium ion (Ca2+)
• D. Chloride ion (Cl-)

Answer: (B)

Verified step by step guidance

1. Understand the concept of osmotic pressure: Osmotic pressure is the pressure required to prevent the flow of water across a semipermeable membrane. It is influenced by the concentration of solutes in a solution.
2. Recognize the role of ions in maintaining osmotic pressure: In biological systems, certain ions help regulate osmotic pressure by balancing the concentration of solutes inside and outside cells.
3. Identify the role of ions in pH balance: pH balance refers to maintaining the acidity or alkalinity of a solution. Some ions can act as buffers, helping to stabilize pH levels in biological systems.
4. Consider the properties of each ion: Sodium ions (Na+) are known for their role in maintaining osmotic pressure and pH balance due to their abundance and ability to move across cell membranes, influencing water movement and pH.
5. Evaluate the function of each ion: While potassium (K+), calcium (Ca2+), and chloride (Cl-) ions have important roles in biological systems, sodium ions (Na+) are particularly crucial for maintaining osmotic pressure and pH balance.