Question

With respect to the phase diagram of copper zinc system. There happens a phase transition at a particular point.  There happens an equilibrium shift consequently. At which point will zinc reach its maximum concentration?

(a) Some point between transition and shift

(b) After transition

(c) Before shift

(d) At the end of both transition and shift

The question was asked in an internship interview.

Question is from Application of Phase Rule to One Component System topic in portion Phase Rule of Engineering Chemistry I

Answer 1

The correct answer is (d) At the end of both transition and shift

The best I can explain: We know that all the transitions (equilibrium and phase transitions) take place within the range 200 to 400 which is the normal equilibrium range. According to Gibbs phase rule, zinc will reach its maximum concentration after equilibrium point that is at the eutectic point.