AbstractThe kinetics and mechanism of the free‐radical chain dechlorination of C2Cl6, C2Cl5H, andsym‐C2Cl4H2in Et3SiH wereinvestigated over a wide temperature range. The propagation step of the dechlorination of chloroethanes (C2ClxH6−x) proceeds by the following reactions:Analysis of the temperature dependence of product formation gave the Arrhenius expressions fork4/k3which in turn were utilized for the estimation of the absolute Arrhenius parameters for hydrogen abstraction from Et3SiH. Our results show that the values ofEabsare lower in Et3SiH than inc‐C6H12by about 2–3 kcal/mol, while theAfactors are almost equal. In competitive studiesk2was determined versus Br abstraction fromn‐C5H11Br. The relative Arrhenius parameters determined by this method show that variations in bothAfactors and activationenergies are responsible for the reactivity trends observed in the Cl transfer reactions of Et3