Correct Option
The correct option is Gas solubility in liquids increases as temperature decreases.
Explanation
The comfort and survival of aquatic species are directly linked to the availability of dissolved oxygen in water. The solubility of gases in liquids is influenced by temperature and pressure, a relationship governed by thermodynamic principles and Henry's Law.
Detailed Analysis
- Gas solubility in liquids increases as temperature decreases is Correct: The dissolution of a gas in a liquid is typically an exothermic process (releasing heat). According to Le Chatelier's principle, increasing the temperature adds heat to the system, shifting the equilibrium to favor the reverse process (gas escaping the liquid). Consequently, the solubility of gases, including oxygen, decreases as temperature increases. Cold water, therefore, holds a higher concentration of dissolved oxygen, facilitating easier respiration for aquatic life.
- Gas solubility is independent of temperature is Incorrect: The solubility of gases in liquids is significantly dependent on temperature; it is not an independent property.
- Cold water has higher density making diffusion faster is Incorrect: While cold water has a higher density than warm water (above 4°C), the primary factor determining the comfort of aquatic species in this context is oxygen availability, not the density of the medium or diffusion rates. In fact, diffusion is generally faster in warmer water due to higher kinetic energy, but the lack of dissolved oxygen outweighs this factor.
- Warm water increases KH which increases solubility is Incorrect: Henry's Law is expressed as \( p = K_H \cdot x \), where \( p \) is the partial pressure of the gas, \( x \) is the solubility (mole fraction), and \( K_H \) is Henry's Law constant. The value of \( K_H \) increases with temperature. Since \( K_H \) and solubility (\( x \)) are inversely proportional at a constant pressure, a higher \( K_H \) in warm water results in lower solubility, not higher.
Key Takeaway: Aquatic species are more comfortable in cold water because the solubility of oxygen is inversely proportional to temperature; colder water retains more dissolved oxygen essential for respiration.