If temperature volume and pressure of fixed amount (say n mole) of a gas vary from T1,V1 and ρ1 to T2,V2 and ρ2 respectively. Then, ideal gas equation for two states can be written as ρ1V1=nRT1 of
ρ1V1
T1
=nR ......(i) ρ2V2=nRT2 of
ρ2V2
T2
=nR ......(ii) on combining Eqs. (i) and (ii), we get