Explain tie-line rule
Tie-line rule is applied to determine the compositions of two co-existing phases in a binary phase diagram. Tie line is a horizontal line drawn at the temperature of interest within two phase region. Tie line rule isn't concerned with phases. It can be applied only in two phase region. Overall compositions of two co-existing phases remain same on the tie-line. There is change only in their relative amounts that is determined by the lever rule.