$(60)$ Using Ellingham diagram, answer following questions:

a$)$ Read the equilibrium partial pressure of $P{O}_2$ for $Al-A{l}_2{O}_3$ and $Ni-$NiO at $1000C$

b$)$ Determine the standard enthalpy and entropy of change at room temperature for $Al-$

$A{l}_2{O}_3$ reaction.

c$)$ To protect $Al$ and $Ni$ from oxidation what must be the oxygen pressure in the test

atmosphere?

d$)$ Assume you put large amount of $Ni$ and $Si$ in the closed furnace with limited air volume

at $1000C.$ What does happen to $Ni$ and $Al$ after reaction with air? Which element or $s$ and

oxide or s do exist when reactions finish? Explain with the values you get above.