What is this part of an aircraft (looks like a long thick pole sticking out of the back)? I need a confirmation. How long will the footprints on the moon last? Synonyms (HF) Hydrofluoric acid, hydrogen fluoride (Fluoride) Variety of compounds, fluoride ion, perfluoride CAS no. Can hydrofluoric acid etch glass at a pH of 7.0? He had some special ones left so I was able to use those. What is the contribution of candido bartolome to gymnastics? Breathing in hydrogen fluoride at high levels or in combination with skin contact can cause death from an irregular heartbeat or from fluid buildup in the lungs. 2 $\begingroup$ I've been looking for a source but I find different results when I try looking for an answer to this. Is it too late for me to get into competitive chess? http://www3.imperial.ac.uk/pls/portallive/docs/1/7276108.PDF, mn-net.com/Testpapers/pHTests/DUOTEST/tabid/10472/language/…, MAINTENANCE WARNING: Possible downtime early morning Dec 2/4/9 UTC (8:30PM…, “Question closed” notifications experiment results and graduation, The influence of lemon juice & sugar on the ph-value. Now Honeywell says that around 5 to 10% it's pH is above 4.4 However if you calculate this using the K a of 6.8 × 10 − 4, you would get about 1.5 pH, which is quite the difference. It is present in a variety of over-the-counter products at concentrations of 6% to 12%. site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. Search Google Scholar for this author, S. Matsuya. M. Nakagawa. Apparently some sources are completely off, doing the calculation based -log(1/H+) gives the correct values in the end, tested for 50, 10, 5, 1 and 0.5%. Copyright © 2020 Multiply Media, LLC. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. It isn't discussed enough here. Why I can't download packages from Sitecore? Asking for help, clarification, or responding to other answers. http://www.endmemo.com/chem/phcal.php. Thanks for contributing an answer to Chemistry Stack Exchange! In soil (pH<6), fluoride is predominantly found in as complexes such as fluorspar, cryolite and apatite and clay minerals. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. It is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers, e.g. In addition, a positive correlation has been noted … I was able to get some rough pH indicators that are allowed in our lab (cleanroom environment). When did organ music become associated with baseball? I found that a method I was hoping to publish is already known. What is the conflict of the story of sinigang? How long was Margaret Thatcher Prime Minister? Viewed 3k times 0. All the calculations based on a value for the $K_a$ of HF acid assume that the concentrations equal the activity of the species. How long does a fresh turkey last in the refrigerator? In surface water at environmentally relevant pH, hydrogen fluoride will dissociate almost entirely to form hydronium and fluoride ions. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Hydrogen fluoride is available commercially either in an anhydrous (water-free) state or in water solutions of various concentrations. Why don't libraries smell like bookstores? PostgreSQL - CAST vs :: operator on LATERAL table function. If a piece of software does not specify whether it is licenced under GPL 3.0 "only" or "or-later", which variant does it "default to"? pH depends on both how strong an acid or base is and how much of it is dissolved in a given amount of water. Hydrogen fluoride gas, even at low levels, can irritate the eyes, nose, and respiratory tract. These are special double indicator strips that do not leave particles, but it's still a visual inspection, so it's an approximate answer. In water, it The absorption of inorganic fluoride across mucous membranes is passive and is independent of the fluoride source. Is there a way to search all eBay sites for different countries at once? No clue why a supplier like Honeywell has completely wrong data. What would be a proper way to retract emails sent to professors asking for help? So other options to achieve this from stock $\ce{HF}$ (49%) with standard chemicals is also an option, however $\ce{NaF}$ is not readily available for me (mostly only access to solutions, such as $\ce{NH4OH}$). The pH of hydrogen fluoride is slightly over 7. What does commonwealth mean in US English? Ask Question Asked 2 years, 4 months ago. http://www3.imperial.ac.uk/pls/portallive/docs/1/7276108.PDF (Honeywell / imperial university) What are the disadvantages of primary group? It is usually shipped in steel cylinders as a compressed gas. HF is commercially available in concentrations ranging from 10% to 49% with 49% HF being the most common. The pH of hydrogen fluoride is slightly over 7. S. Matsuya. In chemistry, pH (/ p iː ˈ eɪ tʃ / ... For example, for a solution with a hydrogen ion activity of 5×10 −6 (at that level, this is essentially the number of moles of hydrogen ions per litre of solution) there is 1/(5×10 −6) = 2×10 5, thus such a solution has a pH of log 10 (2×10 5) = 5.3.

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