Phase Diagrams $(25$ P$)$

Below shown binary phase diagram describes the system CaO$-$MgO.

a$)$ Which phases are present in areas A$,$ B$,$ C$,$ D and E $?(5$ P$)$

A:

D:

B:

E:

C:

b$)$ Please highlight in the diagram the point that indicates the maximum solubility

of MgO in CaO. What is the percentage of MgO at that point $?(2P)$

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

diagram.

d$)$ Briefly explain $$eutectic point$.$ Does the binary system CaO$-$MgO comprise a

eutectic point $?$ If so$,$ please highlight the point in the diagram

e$)$ Please determine composition and fraction x of all phases that are present in a

mixture CaO$/$MgO $(25/75)$ at $2,500$ K in the equilibrium state.

f$)$ The Gibbs phase rule can be written as

F $=$ C $$ P $+2$

with F $=$ degree of freedom

C $=$ number of components

P $=$ number of phases

What is meant by $$degree of freedom$?$ Please determine F for the binary

system CaO$-$MgO at $2,900$ K with the help of above phase diagram and briefly

discuss your result. $(5$ P$)$