If Z is a compressibility factor, van der Waals equation at low pressure

• Gaseous State

If Z is a compressibility factor, van der Waals equation at low pressure can be written as

1. Z = 1+Pb/RT
2. Z = 1-a/(VRT)
3. Z = 1+RT/Pb
4. Z = 1-Pb/RT

Answer

(P+n²a/V²)*(V-nb) = nRT

For 1 mole, (P+a/V²)*(V-b) = RT

PV = RT + Pb - a/V + ab/V²

At low pressure, terms Pb & ab/V² will be negligible as compared to RT.

So, PV = RT - a/V

The correct option is B.