For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is

A. X

B. X + 1

C. X + 2

D. X + 3

Answer: Option C

Solution(By Examveda Team)

Since, phase rule is $$f\left( {{\text{degree of freedom}}} \right) = C - \emptyset + 2$$
Where, $$C=$$  number of components, $$\emptyset = $$  number of phases,
$$ \Rightarrow \emptyset = C - f + 2$$
So for maximum phases $$f$$ should be minimum $$f$$ cant be negative since it denotes number of variables hence $$f = 0$$
So, $$\emptyset = C + 2$$
Given $$C = X \Rightarrow \emptyset = X + 2$$