Sketch $($i$.$e$.$ hand drawing$)$ relative integral molar enthalpy vs mole fraction of $B$ for an A$-$B solution, when A$-$B is

a$)(10$ pts$.)$ Ideal solution

b$)(10$ pts$.)$ Non$-$ideal solution $($Hint: Sketch the two possibilities$)$

$(15$ pts$.)$ For a hypothetical A$-$B solution, composition and activity data for component B are illustrated in the following table.

$\backslash$table$[[x_B,0\mathrm{.}2,0\mathrm{.}4,0\mathrm{.}6,0\mathrm{.}8],[a_B,0\mathrm{.}05,0\mathrm{.}16,0\mathrm{.}48,0\mathrm{.}75]]$

Sketch $a_B$ vs $x_B$ diagram $($i$.$e$.$ roughly draw$).$ What kind of behavior do you observe compared to "ideal behavior"?