At same temperature and pressure, the rate of diffusion of gas ' X ' is 3 3 times that of a gaseous hydrocarbon of molar mass 54 g mol - 1 . The molar mass of X in g mol - 1 is

Step-by-step solution

Rate of diffusion of gas X(r x ) = 3 3   rate of diffusion gaseous hydrocarbon ( r gas ) r x r g = 3 3 = M g M x M g M x = 27 M x   = M g 27 = 54 27   = 2   g   mol - 1