Question

`25.0` litre of natural gas measured at `25^(@)C` and `740 mm` of `Hg` is bubbled through `Pb_((aq))^(2+)` to give `0.535 g` of solid residue. If natural gas contains `H_(2)S`, the only component responsible for the formation of solid residue, calculate the volume `%` of `H_(2)S`, in natural gas.

Answer 1

`underset("Solid residue")(Pb^(2+)+H_(2)srarr PbS+2H^(+))`
Eq.of `H_(2)S=` Eq. of `PbS`
`(w)/(32//2)=(0.535)/(240//2)`
`:. w_(H_(2)S)=7.58xx10^(-2)`
`:.` Moles of `S=(7.85xx10^(-2))/(34)=2.23x10^(-3)`
`:. V_(H_(2)s)=(nRT)/(P)`
`=(2.23xx10^(-3)xx0.0821xx298xx760)/(740)`
`5.6xx10^(-2)`litre
`:. % Vol=(5.6xx10^(2))/(25)xx100= 0.224`