One mole of nitrogen gas at 0.8 atm takes 38 s to diffuse through a pinhole, whereas one mole of an unknown compound of xenon with fluorine at 1.6 atm takes 57s to diffuse through the same hole. Calculate the molecular formula of the compound.

Answer

`XeF_(6)`

Explanation

For the same amount of gas being effused
`(r_(1))/(r_(2)) = (t_(2))/(t_(1)) = (p_(1))/(p_(2)) sqrt((M_(2))/(M_(1))) rArr (57)/(38) = (0.8)/(1.6) sqrt((M_(2))/(28)) rArr M_(2) = 252 g mol^(-1)`
Also, one molecule of unknown xenon-fluoride contain only one Xe atom `[M (Xe) = 131]`, formula of the unknown gas can be considered to be `XeF_(n)`
`rArr 131 + 19n = 252, n = 6.3` hence the unknown gas is `XeF_(6)`