Pure nitrogen gas at $200$ kPa and $25\backslash$deg C is flowing inside

a long circular rubber pipe. The atmospheric air surrounding

the pipe is at $1$ atm and $25\backslash$deg C$,$ with $79$ percent nitrogen and

$21$ percent oxygen. Determine the molar concentrations of

$($a$)$ nitrogen and $($b$)$ oxygen in the rubber at the inner and outer

surfaces of the pipe