OH-

Definition

OH- is the hydroxide ion, a negatively charged ion formed when a water molecule loses a hydrogen ion (H+). This ion plays a crucial role in determining the pH level of a solution and is essential in various chemical reactions, particularly those involving acids and bases. Hydroxide ions are important in biological systems, influencing enzyme activity and cellular functions.

5 Must Know Facts For Your Next Test

1. Hydroxide ions (OH-) are crucial for maintaining the balance of pH in biological systems, as they can neutralize acids.
2. The presence of OH- ions in a solution increases its basicity, which means the solution has a higher pH value.
3. Hydroxide ions can react with hydrogen ions (H+) to form water (H2O), a key reaction in many biochemical processes.
4. In aqueous solutions, the concentration of hydroxide ions is inversely related to the concentration of hydrogen ions, following the relationship: $$[H^+] imes [OH^-] = 1 imes 10^{-14}$$ at 25°C.
5. Hydroxide ions are involved in various metabolic processes, including digestion and cellular respiration, by influencing enzyme activity.

Review Questions

• How do hydroxide ions influence the pH level of a solution?
  • Hydroxide ions (OH-) directly affect the pH level by increasing the basicity of a solution. When OH- ions are present, they can neutralize hydrogen ions (H+), which decreases the overall concentration of H+ and raises the pH value. This relationship illustrates how essential hydroxide ions are for maintaining the acid-base balance necessary for biological functions.
• Compare and contrast the roles of hydroxide ions with hydrogen ions in acid-base chemistry.
  • Hydroxide ions (OH-) and hydrogen ions (H+) play opposing roles in acid-base chemistry. While H+ ions are associated with acidic solutions and contribute to lower pH values by increasing acidity, OH- ions are linked to basic solutions that raise pH levels. Together, they maintain equilibrium in solution, where an increase in one will lead to a decrease in the other, highlighting their interdependence in chemical reactions.
• Evaluate the importance of hydroxide ions in biological systems and their effects on cellular processes.
  • Hydroxide ions (OH-) are vital for various biological processes as they help regulate pH levels within cells and body fluids. The balance between H+ and OH- concentrations affects enzyme activity, metabolic pathways, and cellular respiration. If the concentration of OH- deviates significantly from normal levels, it can disrupt homeostasis, leading to adverse effects on cellular function and overall health.

Related terms

pH:

A measure of the acidity or basicity of a solution, calculated as the negative logarithm of the hydrogen ion concentration.

Acid: A substance that donates protons (H+) to a solution, resulting in an increase in hydrogen ion concentration and typically lowering the pH.

Base: A substance that accepts protons or donates hydroxide ions (OH-) in a solution, leading to a decrease in hydrogen ion concentration and an increase in pH.