Reaction of pyrex glass with Na2CO3 - Journal of Chemical Education

Reaction of pyrex glass with Na2CO3. Edward Poling and G. R. Yohe. J. Chem. Educ. , 1933, 10 (4), p 242. DOI: 10.1021/ed010p242. Publication Date: Apr...
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REACTION of PYREX GLASS with Na,CO, EDWARD POLING

AND

G. R. YOHE

Ohio Wesleren University, Delaware, Ohio

A

S A PART of an experiment with carbon com-

pounds, students in beginning chemistry were asked to heat various carbonates to see whether or not COBcould be driven off. Each test was performed by beating the carbonate in a dry test-tube and conducting any gas liberated into a solution of Ba(0H)z. A number of students reported that they were able to oblam COz from NazCOa in this way. It was suspected that this evolution of COZmight be due to a reaction between the Na2C03and the Pyrex glass test-tube. In order to investigate this possibility, a six-inch length of iron pipe of one-half inch inside diameter, tightly capped at one end, was substituted for the test-tube. The materials heated and the results obtained are tabulated:

Material

Blast Lamp (Dull red heat) (Bright red heat) no CO1 no COI

Bunsen Burner

NanCOa (c.P.) NaaCOa mixed with powdered P m x glass COl evolved NasCOa mixed with powdered common glass no COX

...... small amount of CO%

It is evident from these results that the evolution of COz reported in numerous cases was due to the reaction of the Na2C03 with the glass of the test-tube. I t is also evident that under these conditions the more acidic boro-silicate glass reacts more readily than does common glass with NazC01.