Phase Diagrams $(25$ P$)$

Below shown binary phase diagram describes the system $Sn-Bi.$

a$)$ Which phases are present in areas $W,x,Y$ and $Z?$ What does $$ stand for $?$

b$)$ With the help of above diagram please determine temperature and

concentration of Bi at maximum solubility of Bi in Sn$.$ What can be said about

the solubility of Sn in Bi $?$

c$)$ Briefly explain $$solidus line$$ and highlight the solidus line in above phase

diagram.

d$)$ Briefly explain $$eutectic point$.$ Does the phase diagram Sn$-$Bi comprise

eutectic points $?(3$ P$)$

e$)$ Please determine composition and mass of all phases which are present in

$100$ g of a mixture Sn$/$Bi $(80/20)$ at $100\backslash$deg C in the thermodynamic equilibrium.