Chapter 4, Problem 125CP

Polychlorinated biphenyls (PCBs) have been used extensivelyas dielectric materials in electrical transformers.Because PCBs have been shown to be potentially harmful,analysis for their presence in the environment hasbecome very important. PCBs are manufactured accordingto the following generic reaction:

${\text{C}}_{\text{12}}{\text{H}}_{\text{10}}\text{+}n{\text{Cl}}_{\text{2}}\underset{\text{catalyst}}{\overset{\text{Fe}}{\to }}{\text{C}}_{\text{12}}{\text{H}}_{\text{10-}n}{\text{Cl}}_n\text{+}n\text{HCl}$

This reaction results in a mixture of PCB products. Themixture is analyzed by decomposing the PCBs and thenprecipitating the resulting ${\text{Cl}}^{\text{–}}$ as AgCl.
a. Develop a general equation that relates the averagevalue of n to the mass of a given mixture of PCBsand the mass of AgCl produced.
b. A 0.1947-g sample of a commercial PCB yielded0.4971 g of AgCl. What is the average value of nfor this sample?