  We present an example counter to the widely-accepted concept on equilibrium
states that "Any thermodynamic equilibrium state of two component systems is
determined by specifying 4 thermodynamic variables that include at least 1
extensive variable." which is equivalent to Gibbs' phase rule. We demonstrate
this fact by thought experiments on an A/B binary mixture where temperature,
pressure and chemical potential of the A-species are chosen as the 3 intensive
variables while the number of B-molecules is chosen as the 1 extensive
variable. Our findings also apply to $M (>2)$-component systems.
