Chapter 13, Problem 130E

A 13.03-g sample contains only ethylene glycol $\left({\text{C}}_{\text{2}}{\text{H}}_{\text{6}}{\text{O}}_{\text{2}}\right)$ and propylene glycol $\left({\text{C}}_{\text{3}}{\text{H}}_{\text{8}}{\text{O}}_{\text{2}}\right)$. When the sample is added to 100.0 g of pure water, the resulting solution has a freezing point of -3.50 °C. What was the percent composition of ethylene glycol and propylene glycol in the original sample?