solubility of gas 1

 Here’s a student-friendly, CBSE Class 12–based explanation of the solubility of a gas in a liquid, including the scientific basis, examples, and key law (Henry’s law):

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💨 Solubility of a Gas in a Liquid

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📖 Definition:

The solubility of a gas in a liquid refers to the amount of gas that can dissolve in a given amount of liquid at a specific temperature and pressure.

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📌 Important Factors Affecting Gas Solubility:

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1. Pressure ✅ (Major Effect)

• Gas solubility increases with pressure.

• More pressure pushes more gas particles into the liquid.

📖 Explained by Henry’s Law:

“At constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the solution.”

🧪 Henry’s Law Formula:

$$p = K_H \cdot x$$

Where:

• p = partial pressure of the gas

• x = mole fraction of the gas in solution

• KH = Henry’s law constant

📌 Higher $K_H$ ⇒ Lower solubility

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2. Temperature 🔥 (Opposite Effect)

• Gas solubility decreases with increase in temperature.

• Because gas molecules gain energy and escape more easily.

📖 According to Le Chatelier’s Principle:

Gas dissolution is exothermic, so increasing temperature reduces solubility.

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🔁 Dynamic Equilibrium in Gas Solubility:

$$\text{Gas (in atmosphere)} \rightleftharpoons \text{Gas (dissolved in liquid)}$$

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🧠 Everyday Examples:

Gas	Liquid	Use/Effect
CO₂	Water	Fizzy drinks (soda, cola) – bottled under pressure
O₂	Water	Dissolved oxygen – supports aquatic life
N₂	Blood	Causes bends in scuba divers when pressure suddenly drops

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⚠️ Applications of Henry’s Law (CBSE Short Notes):

• Soft Drinks: Bottled under high pressure to dissolve more CO₂.

• Scuba Diving: Sudden pressure drop causes nitrogen bubbles (bends).

• High Altitude: Low pressure means less O₂ dissolves in blood → causes anoxia (weakness, breathlessness).

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📝 CBSE Exam Tip:

If asked about solubility of gases:

• Always mention pressure and temperature.

• Write Henry’s Law and p = KH·x.

• Give at least 2 applications (like soda or scuba diving).

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Would you like a diagram showing how gas dissolves under pressure or a Henry’s Law graph to add to your class slides?