Question

A gas at 350 K and 15 bar has molar volume 20 percent smaller than that for an ideal gas under the same conditions. The correct option about the gas and its compressibility factor (Z) is :

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• A. Z > 1 and repulsive forces are dominant
• B. Z > 1 and attractive forces are dominant
• C. Z< 1 and attractive forces are dominant
• D. Z < 1 and repulsive forces are dominant

Answer 1

The correct option is C Z< 1 and attractive forces are dominant

Compressibility factor:

$Z=\frac{V_{real}}{V_{ideal}}$
$\because V_{real}<V_{ideal}$
Hence, $Z<1$
If Z < 1, attractive forces are dominant among gaseous molecules and liquefaction of gas will be easy.