A composite foil made of metal A bonded to metal B$,$ each $0\mathrm{.}01cm$ thick, is exposed to a

chamber of pure hydrogen at $0\mathrm{.}5$atm pressure on the material A side; the other side, metal $B,$

is subjected to a perfect vacuum. At the temperature in question and at one atm of hydrogen,

the solubility of hydrogen in metal $A$ is $410-4g\frac{r}{c}m3$ of A and in $B$ is $110-4g\frac{r}{c}m3$ of $B.$ Also,

it is known that the Hydrogen diffuses four times faster in A than in $B$ and that A and $B$ do not

diffuse between themselves. Draw the hydrogen concentration profile through the composite

foil A$-$B$.$ Help: Remember that hydrogen concentration is related to partial pressure $PH2$ and

solubility $S$ as:

$C_H=S\sqrt[\phantom{2}]{p_{H_2}}$