A lead–tin alloy of composition 30 wt% Sn–70 wt% Pb is slowly heated from a temperature of 150°C (300°F). (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? (c) At what temperature does complete melting of the alloy occur? (d) What is the composition of the last solid remaining prior to complete melting? -review of phase diagrams from an early more social time.

Explanation:

(a)The first liquid phase temperature required at 183°C

(b)By drawing a tie line and intersection with the liquidus line, the composition of the first liquid deduced is

61.8wt% of sand

38.2wt% of Pb

(c)By studying the diagram, phase diagram is on liquidus line, then

The complete melting point temperature of alloy is 260°C

(d)If a tie line is drawn it is deduced that thecomposition of the last solid remaining prior to complete melting is 13wt% of Sn

where's the diagram?

there are two significant figures.