Hydrofluoric Acid: A Weak Acid – Yet It Dissolves Glass?

On the far right side of the Periodic Table of the Elements is listed the halogens, which include fluorine, chlorine, bromine, iodine, and astatine. In order of ascending atomic weight we have: fluorine and chlorine gases, bromine liquid, and iodine and astatine solids. Each exhibits a –1 valence. Each attaches to a single atom of hydrogen to form an anhydrous acid. Most of these acids are considered very strong with the exception of hydrofluoric acid. It is comparably a relatively weak acid. This is the case, even though hydrofluoric is the only acid stored in polyethylene bottles because it dissolves glass. Since it can eat its way through glass, how can hydrofluoric acid be considered a weak acid? Hydrofluoric Acid Attacks Glass While hydrofluoric acid is usually written HF, for…
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Does Glass Flow? Is Glass Liquid or Is It Solid?

Chemistry, History
[caption id="attachment_14158" align="alignright" width="440"] Old glass (top); new glass (bottom).[/caption] From childhood, I had been told (and believed) that glass is a liquid. Kids are so trusting! I never doubted what the grown-ups were telling me was gospel truth. Well, is it the truth? Is glass liquid or solid? The answer is (and I say this almost sadly) glass is a solid. Is Glass Liquid Kids may be gullible, but adults should not be. They should know better. So the idea that glass is a liquid—where did the adults get that from? On what evidence was it based? It came from the belief that glass flows. "Evidence" did seem to suggest it. What evidence? [sc name="MidArticleAdsense"] The evidence of the windowpanes. I’m not sure how easy this is to check…
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