Question

The solubility of gases in water can be calculated using

• A. Henry's law
• B. Raout'Fs law
• C. Avagadro's law
• D. Gaylusac's law

Hint:

Remember: Solubility \(\propto\) Pressure. This is why fish can suffocate in warm water (gas solubility decreases as temperature increases, opposite to solids!).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The amount of gas that can dissolve in a liquid depends on the nature of the gas and liquid, temperature, and pressure. Several gas laws describe how these variables interact.
Key Formula or Approach:
The fundamental relationship for gas solubility in a solvent at a constant temperature is described by Henry's Law:
\[ C = k \cdot P \]
where \(C\) is the concentration of the dissolved gas, \(k\) is the Henry's law constant, and \(P\) is the partial pressure of the gas above the liquid.

Step 2: Detailed Explanation:
Henry's Law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas in equilibrium with that liquid. This is why carbonated beverages "fizz" when opened; the pressure is released, the partial pressure of \(CO_2\) drops, and therefore its solubility decreases, causing gas to escape.
Evaluating other laws:
- Raoult's Law (Option 2): Relates the vapor pressure of a solvent to the mole fraction of the solute in a solution.
- Avogadro's Law (Option 3): States that equal volumes of gases at the same temperature and pressure contain an equal number of molecules.
- Gay-Lussac's Law (Option 4): States that the pressure of a given mass of gas is directly proportional to its absolute temperature at a constant volume.
Only Henry's Law specifically addresses gas solubility in liquids.

Step 3: Final Answer:
Henry's Law is the physical principle used to calculate the equilibrium concentration of a dissolved gas based on its partial pressure.