volume(v)=329 cm³×10^(-3) litre=0.329 litre
pressure(p)=1 atm
temperature (t)=20°C=(20+273)K=293K
no of moles of gas=n (=m/M)
given mass=m=2 gm
universal gas constant (R)= 0.0821
molar mass(M)=?
Using the case of ideal gas,
pv=nRt
or,1×0.329=(m/M)× 0.0821 ×293
or,0.329=(2/M)× 0.0821 ×293
or,M=(2× 0.0821 ×293)/0.329
M=48.1106/0.329
M=146.23 g
i.e, molar mass of SX6=146 (approx. value)
molar mass of X6=146-molar mass of S
=146-32=114 (approx.)
➡molar mass of X=114/6=19......which is the molar mass of fluorine (F).
So,the given compound is SF6