Question

why is hydrogen gas and hellium shows only positive deviation​

Answer 1

Answer ;-

Hydrogen And Helium Only Shows Positive Deviations Due To Very Less Interatomic Attraction.....

Explanation ;-

The formula for the compressibility factor is given below

$Z = \frac{PV}{RT} \\ \\ Z= \frac{V_{real}}{ V_{ideal}}$

So when the atom of gas came closer there starts interatomic attraction between the particles which leads to decreases in the volume of gas means

${V_{real}} < { V_{ideal}}$

means the value of z become less than 1......

This is called negative deviation but

In Hydrogen And Helium there is very less force of attraction between the particles (because of there very small size) due to which they don't show negative deviation....

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