Using $Pb-Sn$ eutectic phase diagram answer following questions:

Use $x_{Sn}=at\frac{\%}{100}!$

a$)$ Calculate the Henryian activity coefficient of $Sn$ at the solubility limit at $\frac{300}{x}C$ Assuming all solution $(,$ and $L)$ obeys Regular solution model.

b$)$ Draw activity of $Sn$ vs$.$ mol fraction of $x_{Sn}$ at $\frac{300}{x}C$

c$)$ Plot schematically $G^m$ vs$.x_{Sn}$ curve for solid and liquid solution at $\frac{300}{x}C.$ Show the $G^m$ of alloy vs$.xSn.$

d$)$ Calculate the $G^m$ at two phase regions at average of two phases compositions $($Xsn$).x=$ average of the last two numbers of $S.$ Number. If it is $0$ take $x=1.$