Determine the molarity of a solution prepared by dissolving 5.0 g of NaOH in 450 mL of solution.

1. Determine the molarity of a solution prepared by dissolving 5.0 g of NaOH in 450 mL of solution. 1. 450 mL विलयन में 5.0 g NaOH घोलकर बनाए गए विलयन की मोलरता ज्ञात कीजिए। +

Given Data

Mass of NaOH = 5.0 g
Volume of solution = 450 mL
Molar mass of NaOH = 40 g mol⁻¹

Formula

M = n / V

Where:

M = Molarity
n = Number of moles of solute
V = Volume of solution in litres

Step 1: Calculate Moles of NaOH

Number of moles:

n = Mass / Molar Mass

n = 5.0 / 40

n = 0.125 mol

Step 2: Convert Volume into Litres

Given volume = 450 mL

Since:
1000 mL = 1 L

Therefore:

V = 450 / 1000

V = 0.450 L

Step 3: Calculate Molarity

Using:

M = n / V

M = 0.125 / 0.450

M = 0.2778 mol L⁻¹

Final Answer

The molarity of the NaOH solution is approximately 0.278 M.

Quick Method

M = (Mass × 1000) / (Molar Mass × Volume in mL)

Substituting:

M = (5.0 × 1000) / (40 × 450)

M = 0.278 M

Concept

Molarity is the number of moles of solute present in one litre of solution. Therefore, the volume must always be converted from mL to L before using the formula M = n/V.

दिया गया है

NaOH का द्रव्यमान = 5.0 g
विलयन का आयतन = 450 mL
NaOH का मोलर द्रव्यमान = 40 g mol⁻¹

सूत्र

M = n / V

जहाँ:

M = मोलरता
n = विलेय के मोलों की संख्या
V = विलयन का आयतन लीटर में

चरण 1: NaOH के मोल ज्ञात कीजिए

मोलों की संख्या:

n = द्रव्यमान / मोलर द्रव्यमान

n = 5.0 / 40

n = 0.125 mol

चरण 2: आयतन को लीटर में बदलें

दिया गया आयतन = 450 mL

हम जानते हैं:
1000 mL = 1 L

इसलिए:

V = 450 / 1000

V = 0.450 L

चरण 3: मोलरता ज्ञात कीजिए

सूत्र:

M = n / V

M = 0.125 / 0.450

M = 0.2778 mol L⁻¹

अंतिम उत्तर

NaOH विलयन की मोलरता लगभग 0.278 M है।

सीधी विधि

M = (द्रव्यमान × 1000) / (मोलर द्रव्यमान × आयतन mL में)

मान रखने पर:

M = (5.0 × 1000) / (40 × 450)

M = 0.278 M

Concept

मोलरता वह संख्या है जो बताती है कि एक लीटर विलयन में विलेय के कितने मोल उपस्थित हैं। इसलिए M = n/V सूत्र में आयतन को लीटर में लेना आवश्यक है।

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30 Related MCQs 30 संबंधित MCQs

1. The molar mass of NaOH is:

A. 23 g mol⁻¹

B. 40 g mol⁻¹

C. 58.5 g mol⁻¹

D. 18 g mol⁻¹

Answer: B. 40 g mol⁻¹

2. The number of moles present in 5.0 g NaOH is:

A. 0.025 mol

B. 0.125 mol

C. 0.25 mol

D. 1.25 mol

Answer: B. 0.125 mol

3. 450 mL is equal to:

A. 4.50 L

B. 0.045 L

C. 0.450 L

D. 45.0 L

Answer: C. 0.450 L

4. The formula for molarity is:

A. M = V/n

B. M = n/V

C. M = n × V

D. M = V × mass

Answer: B. M = n/V

5. The molarity of the given NaOH solution is approximately:

A. 0.028 M

B. 0.278 M

C. 2.78 M

D. 27.8 M

Answer: B. 0.278 M

6. Molarity is expressed in:

A. mol kg⁻¹

B. mol L⁻¹

C. g L⁻¹ only

D. kg mol⁻¹

Answer: B. mol L⁻¹

7. Before calculating molarity, 450 mL should be converted into:

A. kg

B. g

C. L

D. mol

Answer: C. L

8. One mole of NaOH has a mass of:

A. 20 g

B. 30 g

C. 40 g

D. 80 g

Answer: C. 40 g

9. The atomic mass of sodium is approximately:

A. 12

B. 23

C. 35.5

D. 40

Answer: B. 23

10. The molecular mass contribution of oxygen in NaOH is:

A. 1

B. 16

C. 23

D. 40

Answer: B. 16

11. The mass contribution of hydrogen in NaOH is:

A. 1

B. 8

C. 16

D. 23

Answer: A. 1

12. If the volume of a solution increases while moles remain constant, molarity:

A. Increases

B. Decreases

C. Becomes zero immediately

D. Remains necessarily constant

Answer: B. Decreases

13. If the amount of solute increases while volume remains constant, molarity:

A. Increases

B. Decreases

C. Remains unchanged

D. Becomes zero

Answer: A. Increases

14. Which quantity is used in the numerator of the molarity formula?

A. Volume

B. Moles

C. Density

D. Temperature

Answer: B. Moles

15. Which quantity is used in the denominator of M = n/V?

A. Mass

B. Moles

C. Volume in litres

D. Molar mass

Answer: C. Volume in litres

16. 1 L is equal to:

A. 10 mL

B. 100 mL

C. 500 mL

D. 1000 mL

Answer: D. 1000 mL

17. If 0.125 mol NaOH is present in 0.450 L solution, its molarity is:

A. 0.0278 M

B. 0.278 M

C. 2.78 M

D. 27.8 M

Answer: B. 0.278 M

18. Molarity is based on the volume of:

A. Solvent only

B. Solution

C. Solute only

D. Container

Answer: B. Solution

19. The unit mol L⁻¹ can also be written as:

A. M

B. m

C. N only

D. kg

Answer: A. M

20. A 1 M solution contains:

A. 1 mole solute per litre solution

B. 1 gram solute per litre

C. 1 mole solvent per litre

D. 1 kg solute per litre

Answer: A. 1 mole solute per litre solution

21. Which formula can directly calculate molarity from mass?

A. M = mass × molar mass / volume

B. M = mass / (molar mass × volume in L)

C. M = volume / mass

D. M = molar mass / mass

Answer: B. M = mass / (molar mass × volume in L)

22. The given solution contains 0.125 mol NaOH. This quantity represents:

A. Mass

B. Number of moles

C. Volume

D. Density

Answer: B. Number of moles

23. If the same 5 g NaOH were dissolved to make 1 L solution, the molarity would be:

A. 0.0125 M

B. 0.125 M

C. 1.25 M

D. 12.5 M

Answer: B. 0.125 M

24. If the same 5 g NaOH were dissolved to make 0.225 L solution, the molarity would be:

A. 0.278 M

B. 0.556 M

C. 1.11 M

D. 2.22 M

Answer: B. 0.556 M

25. Molarity changes with temperature mainly because:

A. Number of atoms changes

B. Volume of solution may change

C. Molar mass changes

D. Atomic number changes

Answer: B. Volume of solution may change

26. Which is NOT needed directly to calculate molarity from mass?

A. Mass of solute

B. Molar mass

C. Volume of solution

D. Atomic number of solvent

Answer: D. Atomic number of solvent

27. The molarity calculated for the given solution to three significant figures is:

A. 0.278 M

B. 0.28 M

C. 2.78 M

D. 27.8 M

Answer: A. 0.278 M

28. In a dilution process, if moles remain constant and volume increases, concentration:

A. Increases

B. Decreases

C. Becomes infinite

D. Always remains unchanged

Answer: B. Decreases

29. The value 0.278 M means approximately:

A. 0.278 mol NaOH per litre solution

B. 0.278 g NaOH per litre

C. 2.78 mol NaOH per litre

D. 278 mol NaOH per litre

Answer: A. 0.278 mol NaOH per litre solution

30. The correct final answer for the given problem is:

A. 0.0278 M

B. 0.278 M

C. 2.78 M

D. 27.8 M

Answer: B. 0.278 M

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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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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 Explanation

The Henry’s Law constant (K_H) is a constant that relates the partial pressure of a gas above a liquid to the concentration or solubility of that gas dissolved in the liquid at a particular temperature. For the commonly used form of Henry’s Law:

P = K_H × x

Where:

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

Therefore:

K_H = P / x

Relation Between K_H and Solubility

For the above convention of Henry’s Law, the relationship is:

Higher K_H → Lower solubility of the gas

Lower K_H → Higher solubility of the gas

Thus, Henry’s Law constant is inversely related to gas solubility when the equation P = K_Hx is used.

K_H ↑ → Solubility ↓

K_H ↓ → Solubility ↑

Why Does Higher K_H Mean Lower Solubility?

From:
P = K_Hx

we can rearrange:
x = P / K_H

At a fixed pressure, if K_H increases, x decreases. Since x represents the amount of gas dissolved in the liquid, a smaller x means lower solubility.

Example

Suppose two gases have the following Henry’s Law constants at the same temperature:

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

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

Lower K_H → More gas dissolves
Higher K_H → Less gas dissolves

Important Note About Different Conventions

Henry’s Law is written in different forms in different textbooks and scientific sources. For example:

P = K_Hx

uses K_H as a pressure/mole-fraction constant, for which a higher K_H means lower solubility.

Another convention may define the constant as the ratio of dissolved concentration to pressure:

C = kP

In that convention, a larger k means greater solubility.

Therefore, always check the exact equation used to define the Henry’s Law constant before comparing numerical values.

Connection with Temperature

For most gases, increasing temperature decreases their solubility. Therefore, under the convention:

P = K_Hx

the Henry’s Law constant generally increases with increasing temperature. Thus:

Temperature ↑
→ K_H ↑
→ Gas Solubility ↓

Final Answer

For the commonly used form P = K_Hx, the Henry’s Law constant is inversely related to the solubility of a gas. At a given pressure, x = P/K_H. Therefore, a larger K_H means lower solubility, whereas a smaller K_H means higher solubility. The exact meaning depends on the convention used to define K_H.

विस्तृत व्याख्या

Henry’s Law Constant (K_H) वह नियतांक है जो किसी द्रव में घुली गैस की मात्रा तथा द्रव के ऊपर उपस्थित गैस के आंशिक दाब के बीच संबंध बताता है। Henry’s Law का एक सामान्य रूप है:

P = K_H × x

जहाँ:

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

इससे:

K_H = P / x

K_H और गैस की विलेयता का संबंध

ऊपर दिए गए Henry’s Law के convention में:

अधिक K_H → कम विलेयता

कम K_H → अधिक विलेयता

अर्थात P = K_Hx वाले convention में Henry’s Law constant गैस की विलेयता के व्युत्क्रमानुपाती होता है।

K_H ↑ → विलेयता ↓

K_H ↓ → विलेयता ↑

अधिक K_H का अर्थ कम विलेयता क्यों?

Henry’s Law:

P = K_Hx

को rearrange करने पर:

x = P / K_H

स्थिर दाब पर यदि K_H बढ़ता है, तो x का मान कम हो जाता है। चूँकि x द्रव में घुली गैस की मात्रा को दर्शाता है, इसलिए x का कम होना गैस की कम विलेयता को दर्शाता है।

उदाहरण

मान लीजिए समान तापमान पर दो गैसों के Henry’s Law constants हैं:

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

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

कम K_H → अधिक गैस घुलेगी
अधिक K_H → कम गैस घुलेगी

महत्वपूर्ण नोट: अलग-अलग Convention

अलग-अलग Chemistry textbooks और scientific sources में Henry’s Law को अलग-अलग रूपों में लिखा जा सकता है।

एक रूप:

P = K_Hx

इसमें K_H अधिक होने का अर्थ सामान्यतः गैस की कम विलेयता है।

दूसरा रूप:

C = kP

इस convention में k अधिक होने का अर्थ गैस की अधिक विलेयता है।

इसलिए numerical question हल करते समय यह देखना बहुत जरूरी है कि Henry’s Law constant को किस equation द्वारा define किया गया है।

तापमान से संबंध

अधिकांश गैसों की विलेयता तापमान बढ़ने पर कम होती है। इसलिए यदि:

P = K_Hx

वाला convention इस्तेमाल किया जाए, तो सामान्यतः तापमान बढ़ने पर K_H बढ़ता है।

तापमान ↑
→ K_H ↑
→ गैस की विलेयता ↓

अंतिम उत्तर

P = K_Hx वाले सामान्य 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 की विलेयता और कम K_H का अर्थ अधिक गैस की विलेयता है। हालांकि K_H की परिभाषा अलग convention में अलग हो सकती है, इसलिए equation को देखकर ही इसका संबंध तय करना चाहिए।

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30 Related MCQs 30 संबंधित बहुविकल्पीय प्रश्न

1. Henry’s Law relates gas solubility mainly to:

A. Atomic number

B. Partial pressure

C. Neutron number

D. Density only

Answer: B. Partial pressure

2. In P = K_Hx, K_H represents:

A. Gas concentration

B. Henry’s Law constant

C. Solvent mass

D. Temperature

Answer: B. Henry’s Law constant

3. 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

4. From P = K_Hx, x is equal to:

A. P × K_H

B. P/K_H

C. K_H/P

D. P + K_H

Answer: B. P/K_H

5. At constant pressure, if K_H increases, solubility:

A. Increases

B. Decreases

C. Remains unchanged

D. Becomes infinite

Answer: B. Decreases

6. A gas having a smaller K_H value in P = K_Hx form is:

A. More soluble

B. Less soluble

C. Completely insoluble

D. Always solid

Answer: A. More soluble

7. The relation between K_H and x at constant P is:

A. Direct

B. Inverse

C. Exponential

D. Constant

Answer: B. Inverse

8. If K_H is doubled at constant pressure, x becomes:

A. Double

B. Half

C. Four times

D. Unchanged

Answer: B. Half

9. Which gas is commonly discussed using Henry’s Law in soft drinks?

A. CO₂

B. NaCl

C. CaCO₃

D. HCl solid

Answer: A. CO₂

10. In the convention P = K_Hx, high K_H indicates:

A. High solubility

B. Low solubility

C. No relation

D. Infinite solubility

Answer: B. Low solubility

11. The Henry’s Law constant depends on:

A. Nature of gas and solvent

B. Temperature

C. Both A and B

D. Atomic number only

Answer: C. Both A and B

12. For most gases, increasing temperature generally:

A. Increases solubility

B. Decreases solubility

C. Has no effect

D. Converts gas to metal

Answer: B. Decreases solubility

13. Under P = K_Hx convention, increasing temperature generally causes K_H to:

A. Increase

B. Decrease

C. Become zero

D. Remain universally constant

Answer: A. Increase

14. Henry’s Law is generally applied at:

A. Constant temperature

B. Constant atomic number

C. Constant neutron number

D. Zero pressure

Answer: A. Constant temperature

15. If K_H is small, gas solubility in P = K_Hx form is:

A. Relatively high

B. Relatively low

C. Zero

D. Impossible to determine

Answer: A. Relatively high

16. Which equation correctly represents the commonly used mole-fraction form?

A. P = K_Hx

B. P = x/K_H

C. x = PK_H

D. P = x²

Answer: A. P = K_Hx

17. If P remains constant and K_H decreases, x:

A. Increases

B. Decreases

C. Becomes zero

D. Remains unchanged

Answer: A. Increases

18. Which statement is correct for P = K_Hx?

A. K_H is directly proportional to solubility

B. K_H is inversely related to solubility

C. K_H has no relation to solubility

D. K_H is always zero

Answer: B. K_H is inversely related to solubility

19. Which factor increases gas solubility at constant temperature?

A. Decreasing partial pressure

B. Increasing partial pressure

C. Increasing K_H only

D. Heating always

Answer: B. Increasing partial pressure

20. The unit of K_H in P = K_Hx depends on:

A. The pressure unit used

B. Atomic number

C. Neutron number

D. Colour of solution

Answer: A. The pressure unit used

21. Henry’s Law constant is a property of:

A. Gas-solvent system

B. Solute only

C. Container only

D. Thermometer only

Answer: A. Gas-solvent system

22. In P = K_Hx, if x increases at constant K_H, P:

A. Increases

B. Decreases

C. Becomes zero

D. Remains unchanged

Answer: A. Increases

23. A gas with high K_H in the P = K_Hx convention requires:

A. Higher pressure for the same dissolved concentration

B. Lower pressure for the same concentration

C. No pressure

D. Zero temperature

Answer: A. Higher pressure for the same dissolved concentration

24. Which factor can change the value of K_H?

A. Temperature

B. Nature of solvent

C. Nature of gas

D. All of these

Answer: D. All of these

25. In the equation C = kP, a larger k indicates:

A. Greater gas solubility

B. Lower gas solubility

C. Zero solubility

D. No solubility

Answer: A. Greater gas solubility

26. Why must the equation defining K_H be checked before comparing values?

A. Different conventions are used

B. K_H is always zero

C. Pressure has no unit

D. Temperature is irrelevant

Answer: A. Different conventions are used

27. At constant pressure, x = P/K_H shows that x is:

A. Directly proportional to K_H

B. Inversely proportional to K_H

C. Independent of K_H

D. Equal to K_H

Answer: B. Inversely proportional to K_H

28. If Gas A has lower K_H than Gas B under the same convention and temperature, Gas A is:

A. More soluble

B. Less soluble

C. Equally soluble always

D. Insoluble

Answer: A. More soluble

29. Which statement about Henry’s Law is most accurate?

A. It relates gas pressure and dissolved gas concentration

B. It relates atomic mass and pressure

C. It applies only to solids

D. It states that all gases have identical solubility

Answer: A. It relates gas pressure and dissolved gas concentration

30. In the convention P = K_Hx, the correct relationship is:

A. K_H ↑ → Solubility ↑

B. K_H ↑ → Solubility ↓

C. K_H ↑ → Pressure ↓ necessarily

D. K_H has no connection with solubility

Answer: B. K_H ↑ → Solubility ↓

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