SATHEE: States of Matter - Result Question 98

States of Matter - Result Question 98

####2. Consider the following table.

$G a s$	$a / ((k P a d m m o l^{- 1})$	$b / (d m^{3} m o l^{- 1})$
$A$	642.32	0.05196
$B$	155.21	0.04136
$C$	431.91	0.05196
$D$	155.21	0.4382

$a$ and $b$ are van der Waals’ constants. The correct statement about the gases is

(2019 Main, 10 April I)

(a) gas $C$ will occupy lesser volume than gas $A$ ; gas $B$ will be lesser compressible than gas $D$

(b) gas $C$ will occupy more volume than gas $A$ ; gas $B$ will be more compressible than gas $D$

(d) gas $C$ will occupy more volume than gas $A$ ; gas $B$ will be lesser compressible than gas $D$

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Answer:

Correct Answer: 2. (c)

Solution:

For 1 mole of a real gas, the van der Waals’ equation is

$(p + \frac{a}{V^{2}}) (V - b) = R T$

The constant ’ $a$ ’ measures the intermolecular force of attraction of gas molecules and the constant ’ $b$ ’ measures the volume correction by gas molecules after a perfectly inelastic binary collision of gas molecules.

For gas $A$ and gas $C$ given value of ’ $b$ ’ is

$0.05196 d m^{3} m o l^{- 1}$ . Here,

$a \propto$ intermolecular force of attraction

$\propto$ compressibility $\propto$ real nature

$\propto \frac{1}{volume occupied}$

Value of $a / (k P a d m^{6} m o l^{- 1})$ for gas $A (642.32) > gas C (431.91)$ So, gas $C$ will occupy more volume than gas $A$ . Similarly, for a given value of $a$ say $155.21 k P a d m^{6} m o l^{- 1}$ for gas $B$ and gas $D$

$\frac{1}{b} \propto$ intermolecular force of attraction

$\propto$ compressibility $\propto$ real nature

$\propto \frac{1}{volume accupied}$

$b / (d m^{3} m o l^{- 1})$ for gas $B (0.04136) < Gas D (0.4382)$

So, gas $B$ will be more compressible than gas $D$ .

States of Matter - Result Question 98

Answer:

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States of Matter - Result Question 98

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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