⚖️ Henry’s Law – Linked with Dalton’s Idea

 

⚖️ Henry’s Law – Linked with Dalton’s Idea

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🔍 What is Henry’s Law?

Henry’s Law states that:
At constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the surface of the liquid.

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🧪 Mathematical Form:

$$p = K_H \cdot x$$

Where:

• p = partial pressure of the gas

• x = mole fraction (solubility) of the gas in the solution

• K_H = Henry’s law constant

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📘 How is Dalton Related to Henry’s Law?

• John Dalton, a contemporary of William Henry, also studied gases and proposed:

  The solubility of a gas in a liquid depends on its partial pressure in a gas mixture.

• Dalton’s contribution laid the foundation for understanding how each gas behaves independently in a mixture — a principle that complements Henry’s Law.

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🔗 The Link Between Henry and Dalton:

Concept	Dalton	Henry
Focus	Partial pressure of gases	Solubility of gas in a liquid
Common Variable	Partial pressure (p)	Partial pressure (p)
Connection	p controls gas behavior	p controls how much gas dissolves
Conclusion	p↑ → more gas molecules	p↑ → more gas dissolves (x↑)

So, both scientists recognized the importance of partial pressure, but:

• Dalton focused on how gases behave in mixtures,

• Henry focused on how gases dissolve in liquids under that pressure.

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📈 Graph (Henry’s Law):

Plot of p vs x (mole fraction) gives a straight line, slope = K_H

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📝 CBSE Board Tip:

In a long answer or concept explanation, you can write:

"Dalton concluded that the solubility of a gas is a function of its partial pressure. Henry developed this further into a quantitative law, showing the direct proportionality between solubility and partial pressure at constant temperature."

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Would you like a slide design that includes both Henry and Dalton side by side, or a timeline graphic to show their contributions visually in class?