A researcher runs two separate, meticulously controlled experiments. In Experiment I, exactly 1 mole — Haloalkanes and Haloarenes Chemistry Question
Question
A researcher runs two separate, meticulously controlled experiments. In Experiment I, exactly 1 mole of pure $(R)-2$ -pentanol is reacted with $SOCl_2$ in inert ether. In Experiment II, exactly 1 mole of pure $(R)-2$ -pentanol is reacted with $PCl_3$. Assuming 100% theoretical stereospecificity and perfect yield for both recognized reactions, what is the absolute total number of moles of $(S)-2$ -chloropentane that are successfully produced and isolated combined across both entire experiments?
💡 Solution & Explanation
Let's evaluate the stereochemical outcome of each standard reaction. Experiment I: The reaction of an alcohol with $SOCl_2$ in the absence of a base perfectly follows the $S_Ni$ mechanism, demanding complete retention of configuration. Thus, 1 mole of $(R)-2$ -pentanol uniquely yields 1 mole of $(R)-2$ -chloropentane ($0$ moles of the $S$ -isomer). Experiment II: The reaction of an alcohol with $PCl_3$ perfectly follows the $S_N2$ mechanism, demanding complete Walden inversion of configuration. Thus, 1 mole of $(R)-2$ -pentanol uniquely yields 1 mole of $(S)-2$ -chloropentane. Combining the experiments, exactly 1 total mole of the $(S)$ -isomer is produced.