How does the Henry’s Law constant (KH​) relate to the solubility of a gas in a liquid?

1. How does the Henry’s Law constant (K_H) relate to the solubility of a gas in a liquid? 1. हेनरी के नियम नियतांक (K_H) का किसी द्रव में गैस की विलेयता से क्या संबंध है? +

Detailed Answer

The Henry’s Law constant (K_H) expresses the relationship between the partial pressure of a gas above a liquid and the amount of that gas dissolved in the liquid at a particular temperature.

P = K_Hx

Where:

P = partial pressure of the gas
K_H = Henry’s Law constant
x = mole fraction of the dissolved gas

Relation with Solubility

From the equation:

P = K_Hx

we get:

x = P / K_H

At constant pressure, the solubility of the gas is inversely proportional to K_H.

Therefore:

Higher K_H → Lower solubility
Lower K_H → Higher solubility

K_H ↑ → Solubility ↓

K_H ↓ → Solubility ↑

Why?

If K_H is large, a greater gas pressure is required to maintain the same dissolved concentration. Hence, the gas has a lower tendency to remain dissolved in the liquid.

If K_H is small, a relatively small pressure can maintain a larger amount of dissolved gas. Thus, the gas is more soluble.

Example

Consider two gases at the same temperature:

Gas A: K_H = 20 atm
Gas B: K_H = 50 atm

At the same pressure, Gas A will have greater solubility because its K_H value is smaller.

Effect of Temperature

For most gases, solubility decreases as temperature increases. In the convention P = K_Hx, K_H generally increases with temperature.

Temperature ↑ → K_H ↑ → Solubility ↓

Important Note

Different textbooks may use different definitions of Henry’s Law constant. For example, if the equation is written as:

C = kP

then a larger value of k means greater solubility. Therefore, always check the equation used to define the constant before interpreting its numerical value.

Final Answer

For the convention P = K_Hx, Henry’s Law constant is inversely related to the solubility of a gas. At constant pressure, x = P/K_H. Therefore, a higher K_H means lower gas solubility, while a lower K_H means higher gas solubility.

विस्तृत उत्तर

Henry’s Law constant (K_H) गैस के आंशिक दाब और द्रव में घुली हुई गैस की मात्रा के बीच संबंध बताता है। यह संबंध एक निश्चित तापमान पर लागू होता है।

P = K_Hx

जहाँ:

P = गैस का आंशिक दाब
K_H = Henry’s Law constant
x = द्रव में घुली गैस का mole fraction

विलेयता से संबंध

समीकरण:

P = K_Hx

से:

x = P / K_H

स्थिर दाब पर गैस की विलेयता K_H के व्युत्क्रमानुपाती होती है।

अर्थात:

अधिक K_H → कम विलेयता
कम K_H → अधिक विलेयता

K_H ↑ → विलेयता ↓

K_H ↓ → विलेयता ↑

ऐसा क्यों होता है?

यदि K_H का मान अधिक है, तो समान मात्रा में गैस को द्रव में घुलाए रखने के लिए अधिक गैस दाब की आवश्यकता होती है। इसलिए गैस की द्रव में विलेयता कम होती है।

यदि K_H का मान कम है, तो कम दाब पर भी अधिक गैस द्रव में घुली रह सकती है। इसलिए गैस अधिक soluble होती है।

उदाहरण

समान तापमान पर:

Gas A: K_H = 20 atm
Gas B: K_H = 50 atm

समान pressure पर Gas A की विलेयता अधिक होगी क्योंकि उसका K_H कम है।

तापमान का प्रभाव

अधिकांश गैसों की विलेयता तापमान बढ़ने पर कम होती है। P = K_Hx वाले convention में तापमान बढ़ने पर सामान्यतः K_H बढ़ता है।

तापमान ↑ → K_H ↑ → गैस की विलेयता ↓

महत्वपूर्ण नोट

अलग-अलग पुस्तकों में Henry’s Law constant को अलग-अलग तरीके से define किया जा सकता है।

उदाहरण:

C = kP

इस convention में k का अधिक मान अधिक gas solubility को दर्शाता है। इसलिए numerical question में पहले यह देखना आवश्यक है कि K_H किस equation द्वारा define किया गया है।

अंतिम उत्तर

P = K_Hx वाले convention में Henry’s Law constant गैस की विलेयता के व्युत्क्रमानुपाती होता है। स्थिर दाब पर x = P/K_H होता है। इसलिए अधिक K_H का अर्थ कम गैस विलेयता तथा कम K_H का अर्थ अधिक गैस विलेयता है।

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30 Related MCQs 30 संबंधित MCQs

1. Henry’s Law constant is represented by:

A. K_H

B. K_a

C. K_b

D. K_w

Answer: A. K_H

2. In P = K_Hx, x represents:

A. Pressure

B. Mole fraction of dissolved gas

C. Temperature

D. Volume

Answer: B. Mole fraction of dissolved gas

3. From P = K_Hx, x is:

A. P/K_H

B. PK_H

C. K_H/P

D. P + K_H

Answer: A. P/K_H

4. At constant pressure, increasing K_H causes solubility to:

A. Increase

B. Decrease

C. Remain constant

D. Become infinite

Answer: B. Decrease

5. At constant pressure, decreasing K_H causes solubility to:

A. Increase

B. Decrease

C. Become zero

D. Remain unchanged

Answer: A. Increase

6. In P = K_Hx, K_H and solubility are:

A. Directly related

B. Inversely related

C. Always equal

D. Unrelated

Answer: B. Inversely related

7. A gas with lower K_H is generally:

A. More soluble

B. Less soluble

C. Insoluble

D. Solid

Answer: A. More soluble

8. A gas with higher K_H requires what for the same dissolved concentration?

A. Higher pressure

B. Lower pressure

C. Zero pressure

D. No pressure

Answer: A. Higher pressure

9. Henry’s Law connects gas solubility with:

A. Partial pressure

B. Atomic radius

C. Ionisation energy

D. Electronegativity

Answer: A. Partial pressure

10. The solubility of most gases with increasing temperature:

A. Increases

B. Decreases

C. Remains unchanged

D. Becomes infinite

Answer: B. Decreases

11. In P = K_Hx convention, temperature increase generally causes K_H to:

A. Increase

B. Decrease

C. Become zero

D. Become independent of temperature

Answer: A. Increase

12. Which gas is commonly used as an example in carbonated drinks?

A. CO₂

B. NaCl

C. CaO

D. Fe

Answer: A. CO₂

13. If P is doubled and K_H remains constant, x will:

A. Double

B. Halve

C. Become zero

D. Remain unchanged

Answer: A. Double

14. If K_H is doubled at constant P, x will:

A. Double

B. Become half

C. Become four times

D. Remain unchanged

Answer: B. Become half

15. Henry’s Law is generally considered at:

A. Constant temperature

B. Constant atomic number

C. Constant neutron number

D. Zero pressure

Answer: A. Constant temperature

16. Which equation is the mole-fraction form of Henry’s Law?

A. P = K_Hx

B. P = x/K_H

C. x = PK_H

D. P = x²

Answer: A. P = K_Hx

17. At constant pressure, x is proportional to:

A. K_H

B. 1/K_H

C. K_H²

D. Zero

Answer: B. 1/K_H

18. Henry’s Law constant depends on:

A. Temperature

B. Nature of gas

C. Nature of solvent

D. All of these

Answer: D. All of these

19. A lower K_H generally indicates:

A. Greater gas solubility

B. Lower gas solubility

C. No dissolution

D. Gas solidification

Answer: A. Greater gas solubility

20. In P = K_Hx, P represents:

A. Partial pressure

B. Mole fraction

C. Temperature

D. Mass

Answer: A. Partial pressure

21. If Gas A has K_H = 10 and Gas B has K_H = 40, which is more soluble?

A. Gas A

B. Gas B

C. Both equally

D. Cannot ever dissolve

Answer: A. Gas A

22. Which change generally increases gas solubility?

A. Increase pressure

B. Increase temperature

C. Decrease pressure

D. Boil the solution

Answer: A. Increase pressure

23. In the convention P = K_Hx, K_H is best described as:

A. Pressure required per unit mole fraction

B. Temperature per mole

C. Mass per volume

D. Density constant

Answer: A. Pressure required per unit mole fraction

24. Which statement is correct?

A. Higher K_H means higher solubility in every convention

B. The equation defining K_H must be checked

C. K_H is always dimensionless

D. K_H is independent of temperature

Answer: B. The equation defining K_H must be checked

25. In C = kP convention, a larger k means:

A. Higher solubility

B. Lower solubility

C. No solubility

D. Zero concentration

Answer: A. Higher solubility

26. Gas solubility is generally higher when temperature is:

A. Lower

B. Higher

C. Infinite

D. Always irrelevant

Answer: A. Lower

27. A high K_H gas has:

A. Greater tendency to dissolve

B. Lower solubility under P = K_Hx convention

C. Infinite solubility

D. No pressure requirement

Answer: B. Lower solubility under P = K_Hx convention

28. Which statement follows from x = P/K_H?

A. Increasing pressure increases solubility

B. Increasing K_H increases solubility

C. Pressure has no effect

D. K_H is equal to x

Answer: A. Increasing pressure increases solubility

29. The value of K_H can change when:

A. Temperature changes

B. The gas changes

C. The solvent changes

D. All of these

Answer: D. All of these

30. For P = K_Hx, the correct relationship is:

A. K_H ↑ → Solubility ↑

B. K_H ↑ → Solubility ↓

C. K_H has no effect

D. Solubility is always zero

Answer: B. K_H ↑ → Solubility ↓

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