Chapter 5, Problem 5E.2DQ

Interpretation Introduction

Interpretation: Whether the lever rule applies to the ternary system or not has to be stated.

Concept introduction: The ternary system is defined as the system having three components.  These components in a mixture on undergoing the phase changes represent a triangular phase diagram.  Thus, the three dimensional representation of the phase diagram is given for the ternary system.

The lever rule is used to determine the relative amount of the components in the phases which are represented in the phase diagram.  According to the lever rule, the ratio of composition of each phase of a component is equal to the ratio of distances in the phase diagram.  It is represented by the formula as,

    $\frac{n_{\alpha }}{n_{\beta }}=\frac{l_{\beta }}{l_{\alpha }}$