Q.

A given sample of an ideal gas occupies a volume V at a pressure P and absolute temperature T. The mass of each molecule of the gas is m. Which of the following gives the density of the gas              [2016]
 

1 P(kT)  
2 Pm(kT)  
3 P(kTV)  
4 mkT  

Ans.

(2)

As PV=nRT

or  n=PVRT=massmolar mass                       ...(i)

Density, ρ=massvolume=(molar mass)PRT=(mNA)PRT

   ρ=mPkT                                             (R=NAk)