The compressibility factor for a real gas at high pressure is .

Options

A. 1
B. `1+(Pb)/(RT)`
C. `1-(pb)/(RT)`
D. `1+(RT)/(Pb)`

Answer

B

Explanation

van der Waals equation for one mole of a real gas is `(P+a/(V^(2)))(V-b)=RT`
or `PV=RT+Pb+(ab)/(V^(2))-a/V`
At high pressure, then van der Waals gas equation reduces to `PV=RT+Pb,` or `(PV)/(RT)=1+(Pb)/(RT)`
`therefore` Compressibillity factor `Z=(PV)/(RT)=1+(Pb)/(RT)`