4. Two kilograms of an alloy of 60 percent Pb and 40 percent Sn is cooled from its liquid state from 300°C. Use Lead-Tin phase diagram in the text book and answer the following.

 a. Calculate the weight percent of the liquid at 250°C. (0.5 point). 

b. Calculate the weight percent of the proeutectic alpha at 250°C. (0.5 point).

 c. Calculate the weight percent of liquid phase just above the eutectic temperature (183°C) and weight in kilograms of this phase. (1 point).

 d. Calculate the weight percent of proeutectic alpha phase just above the eutectic temperature (183°C) and weight in kilograms of this phase. (1 point)

 e. Draw microstructure that can possibly be observed for above Lead-Tin alloy at room temperature. (1 point\n