In This post you will get answer of Q.
Equation of a gas in terms of pressure (P), absolute temperature, (T) and density (rf) is:

Solution:

Gas equation is $ frac{PV}{T}=constan t=R $ or $ frac{{{P}_{1}}{{V}_{1}}}{{{T}_{1}}}=frac{{{P}_{2}}{{V}_{2}}}{{{T}_{2}}} $ If m is the mass of a gas and $ {{d}_{1}} $ and $ {{d}_{2}} $ are its density at absolute temperature $ {{T}_{1}}K $ and $ {{T}_{2}}K, $ then $ {{V}_{1}}=m/{{d}_{1}} $ and $ {{V}_{2}}=m/{{d}_{2}} $ $ therefore $ $ frac{{{P}_{1}}}{{{T}_{1}}}left ( frac{m}{{{d}_{1}}} right)=frac{{{P}_{2}}}{{{T}_{2}}}left( frac{m}{{{d}_{2}}} right) $ $ frac{{{P}_{1}}}{{{T}_{1}}{{d}_{1}}}=frac{{{P}_{2}}}{{{T}_{2}}{{d}_{2}}} $