Consider the following table: \begin{tabular}{lll} Gas & \(\mathrm{a} /(\mathrm{k} \mathrm{Pa} \mathrm{dm}^{6} \mathrm{~mol}^{-1})\) & \(\mathrm{b} /(\mathrm{dm}^{3} \mathrm{~mol}^{-1})\) \\ A & 642.32 & 0.05196 \\ B & 155.21 & 0.04136 \\ C & 431.91 & 0.05196 \\ D & 155.21 & 0.4382 \end{tabular} \(a\) and \(b\) a van der Waals constants. The correct statement about the gases is:

(D) Gas C will occupy more volume than gas A; gas B will be more compressible than gas D.

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

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

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

JEE Main · 2019 · 10 Apr 2019 · Shift 1 · States of Matter

Consider the following table:

\begin{tabular}{lll}
Gas &

a / (k Pa dm^{6} mol^{- 1})

b / (dm^{3} mol^{- 1})

\\
A & 642.32 & 0.05196 \\
B & 155.21 & 0.04136 \\
C & 431.91 & 0.05196 \\
D & 155.21 & 0.4382
\end{tabular}

a

and

b

a van der Waals constants. The correct statement about the gases is:

(A)Gas C will occupy more volume than gas A ; gas B will be lesser compressible than gas D
(B)Gas C will occupy lesser volume than gas A ; gas B will be more compressible than gas D.
(C)Gas C will occupy lesser volume than gas A ; gas B will be lesser compressible than gas D
(D)Gas C will occupy more volume than gas A; gas B will be more compressible than gas D.✓ Correct

Answer: (D)

Solution

The van der Waals constant

a

measures intermolecular attraction and

b

the excluded volume. Gases A and C share the same

b

but A has the larger

a

(

642.32

against

431.91

), so A's molecules are held more tightly and C ends up occupying the greater volume. Gases B and D share the same

a

but D has the far larger

b

(

0.4382

against

0.04136

), so D has less free space and resists compression most, leaving B the more compressible of the two. So C occupies more volume than A, and B is more compressible than D.

JEE Main · 2019 · 10 Apr 2019 · Shift 1 · Single correct option

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JEE Main · 2019 · 10 Apr 2019 · Shift 1 · States of Matter

Solution

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