A Simple and Convenient Method to Prepare Hydrogen Chloride Gas Hydrogen chloride is a commonly used gas in research, high school, and college laboratories. Very recently Thomas' has presented a method t o generate hydrogen chloride gas in laboratory by using hydrochloric acid and anhydrous lithium chloride. The anhvdrous lithium chloride is not a common salt available in most high school and calleee laboratories. In .~ ,~~~~~~ addition, lithium waste produrcd during hydrogen chloride gas preparation is also a disposal problem. I present here a simple and convenient method far preparrng hydrogen chloride gas without producing any waste and uring chemicals commonly available in laboratories. Caution: The following reaction must be conducted in a well-ventilated hood. To prepare hydrogen chloride gas, t o a 500-mL Erlenmeyer flaskfitted with a pressure-equalizing dropping funnel and gas outlet is placed 100 mL concentrated sulfuric acid (36 MI.Through a dropping funnel 100 mL of concentrated hvdrochloric acid (12.5 M)is added slowly t o the concentrated sulfuric acid while stirrinp. Evolution of hydrogen chloride &s occurs immediately and the gas may he used sa desired. The vdume of the rrautantskay be adpted~arc&dingto the hydrogen chloride gas requirement. The very dilute sulfuric acid obtained at the end of the proresr may he dlsposed of hy ilushing down the drain with water. ~~~~
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'Thomas. N. C. J. Chem. Educ. 1900,67.431
Mannar R. Maurya Iowa State University Ames, IA 50011
974
Journal of Chemical Education
