Talk:Hydrogen sulfide

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[edit] Dissociation constant controversy

I am a bit confussed regarding the second dissociation constant.

The second dissociation constant of hydrogen sulfide is often stated to be around 10−13, but it is now clear that this is an error caused by oxidation of the sulfur in alkaline solution. The current best estimate for pKa2 is 19±2.[2]

Is it so clear?

A search in the internet on these values often gives 10-13. For example: In the journal of the electorchemical society "Electrochemical identification of the hydrogen sulphide system..." J. Electrochem. Soc ., Volume 145, Issue 1 pp77-79 (Jan 1998) gives the value as 13.86. The abstract states "The controversy on the dissociation constant is discussed". This reference post dates the Wikipedia reference (2). I thought controversy should be avoided in Wikipedia. At least a few words on this "controversy" would help the non expert like myself to understand which figure might be correct.

--SlipTimeKnot 09:59, 19 April 2006 (UTC)

[edit] possibe error?

The artical says that "carbon disulfide burns to sulfur dioxide, which can be smelled when mathes are ignighted" Considering that CS2 is a gas, it seems highly unlikely that matches contain it. Anybody know for sure.

(You mean H2S rather than CS2.) I think you have a point: the sentence is misleading. While it is true that H2S burns to SO2, and it is true that SO2 can be smelled when lighting a match, the juxtaposition implies that lighting a match burns H2S, which is not true. AxelBoldt 00:14, 21 December 2005 (UTC)

[edit] Olfactory nerve paralysis

The article states that, after an initial strong exposure, the olfactory nerve is paralysed, preventing a person to perceive the smell of hydrogen sulfide. Does anyone know if this is a temporary paralysis, or a reversible one?

For moderate exposures, I'm pretty sure that it's more-or-less reversable, but a few years ago I was reading some work on rat experiments where the doses were well into the "olfactory paralysis" ranges for humans ; for some of the unfortunate rats their response included sloughing the linings of their nasal passages. With damage like that, permanent loss of sense of smell is plausible. Killing of the nasal nerves is also possible, even if the olfactory organs remain in place and alive.

I haven't heard the question addressed in the many industrial H2S-safety courses I've had to sit through (at least 10, possibly 15 or more). The theory being that if you ever get exposed to that level of H2S, then you're in a personal survival mode, you and several other people have fucked up quite severely, and there have been major equipment failures too. By which point, you're in serious fear of getting dead, and losing your sense of smell isn't very high on your list of priorities. (I've been threatened with being run-off jobs for reporting H2S levels of a few PPM, barely 0.02 of the levels needed to induce olfactory paralysis ; that's me doing my job responsibly and a supervisor being dangerous.)

A Karley 22:24, 19 June 2007 (UTC)

[edit] Americanisation

I know this is going to be unpopular (Wikipedia being an American based website) but the American spelling of the article is chemically incorrect unless you can proove otherwise (knowledge as a chemistry student admittedly in a British Sixth Form, and my sources are the textbooks I use), please move this to Hydrogen Sulphide as I don't seem to be able to. Argue about it if you want, but I'm sticking by my guns sorry! and Im not particularly anti-American if you are wondering, Im a A-Level student! lol Medscin 19:12, 12 January 2006 (UTC)

Both IUPAC and the Royal Society of Chemistry have adopted the spelling of sulfur with an 'f'. But take heart, we use aluminium poop fart weinerversion, aluminum. See Sulfur#Spelling. Edgar181 20:09, 12 January 2006 (UTC)
Fair dos as we at my college say, and ta for the spelling alteration, sorry! it's not a word I commonly use (i.e. Americanization), however how come my textbooks, the exam board, and my teacher spell it as sulphur like that if the RSc spell it as Sulfur?. Medscin 21:11, 12 January 2006 (UTC)
Old habits don't change easily, I guess. Americans still use British units instead of metric. Edgar181 21:39, 12 January 2006 (UTC)
To clarify - IUPAC, RSC and multiple others have ACCEPTED that there are two alternative spellings for sulPHur, sulFur, aluminIUM and aluminUM, and said that they're effectively not interested in getting into a pissing contest about it. As long as there's no ambiguity, there's not an issue to interest anyone other than linguistic and orthographic historians. And spelling Nazis. Godwin's Law Whether the F or the PH spelling is more common is probably dependent on whether the majority of major chemistry journals are edited in America or in the Rest of The World. A Karley 22:36, 19 June 2007 (UTC)

I would imagine it was named Sulphur when first discovered. An American's idea of a consensus is to impose their spellings on things that pre-date their oh so young and ever so slightly borrowed language.—Preceding unsigned comment added by 82.31.42.97 (talk • contribs)

Chemistry has decided to follow IUPAC rules, where sulfur is spelled with an f .. that is what we adhere to. Endless reversions will not change the spelling that you want to use. --Dirk Beetstra T C 12:40, 23 October 2006 (UTC)

[edit] Solubility

I've reverted an anon's edit to the solubility value. It may have been correct, but there was accompanying deletion which looked as if it may have been inadvertent. Can anyone confirm the value? Noisy | Talk 15:27, 26 April 2006 (UTC)

[edit] Bond angle

H20 has a near-tetrahedral bond angle because of molecular orbital hybridization. I seem to remember that H2S and H2Se have different chemistries because they don't hybridize, so the bond angle is nearly 90 degrees one would expect from an s-s bond and a s-p bond. I'm not near a chemistry library now. Anyone know for sure?

I'm nowhere near a chemistry library either, but from memory the bond angle is about 95°. This can be explained either by hybridisation or by VSEPR theory. Physchim62 (talk) 14:00, 14 July 2006 (UTC)

[edit] Further nomeclature

I would suggest the term sour gas be added as a further name for hydrogen sulphide. this term is more generally used in the oil and gas industry.

The only time I hear "sour gas" used in the oil industry (where I've worked for the last 20 years) has been in H2S safety courses in phrases like "you may also hear sour gas being used as a synonym for H2S" ; at least in the circles I work in, most people are degree-educated and professional with it apart form some of the roughnecks, who don't need to be told what may have been common practice when drilling with wooden derricks and steam engines onshore in America two generations ago. The term is of historical interest only. Which is valid, in a historical context. A Karley 22:43, 19 June 2007 (UTC)

[edit] Acretion of dangers warnings

The article about an important chemical compound is slowly acreting a lot of stuff about its hazards. much of it anecdotal. As was done on aniline and hydrazine, much of this material is likely to be compactable into one or two sentences. One can consult an MSDS to get better information.--Smokefoot 20:38, 13 August 2006 (UTC)

I cut it down drastically. This should be enough. --Dirk Beetstra T C 20:45, 13 August 2006 (UTC)

[edit] How many people have ever smelled rotten eggs??

I am always amused by statements such as in the "Toxicity section" of this article, namely: "0.0047 ppm is the recognition threshold, the concentration at which 50% of humans can detect the characteristic rotten egg odor of hydrogen sulfide". I would guess that less than 1 person in 10,000 of us has ever smelled a rotten egg ... so how can that be the characteristic odor? It would be much more useful to describe the odor as that of flatulence (in other words, a fart) because almost all of us have been subjected to that odor at one time or another. Before you remind me, I know that the rotten egg terminology is in all the textbooks and encyclopedias ... but, I repeat, that perhaps less than 1 person in 10,000 has ever smelled a rotten egg. - mbeychok 05:49, 2 January 2007 (UTC)

This has always amused me too. The problem with the "flatulence" comparison is that flatulence is also highly variable. Personally, if someone wants to know what H2S smells like, I tell them to come and give me a hand checking/ calibrating the H2S detectors in our gas package, and give them a sniff of the 5ppm calibration gas mix. The benefits in education outweigh the (minuscule) risk of the procedure. A Karley 22:49, 19 June 2007 (UTC)
The "Rotten Egg" smell is used commonly in stink bombs and other gag paraphenalia, I believe algae smells like this as well. —Preceding unsigned comment added by 209.175.17.2 (talk) 16:11, 7 November 2007 (UTC)
I smelled a rotten egg once. We should create a userbox for that! ("This user has smelled a rotten egg"; Category:Wikipedians who have smelled rotten eggs) --Itub 18:14, 8 November 2007 (UTC)
I have smelt rotten egg several times. You should have seen my friend's kitchen... or perhaps not. --smidoid —Preceding unsigned comment added by Smidoid (talk • contribs) 17:25, 23 March 2008 (UTC)

[edit] Vapour Density

The mention regarding the gas vapour density effect on its behaviour is correct if it relates to pure H2S which is not very common. At the low concentrations normally associated with this gas the characteristics of the carrying fluid (liquid or gas) have the greater influence.

10,000ppm = 1% i.e. 99% of something else.

It is found in low lying areas when it is associated with a liquid. The main influences in the hydrocarbon industry on the gas behaviour is the velocity of any pressurised leak of the carrying gas (e.g. methane) and wind speed and direction. A pressurised leak also causes turbulence resulting in a mixing of the gas with the atmosphere producing further dilution often resulting in a gas air mixture with a vapour density close to that of air.

However it is still possible to see procedures advising people to gain height during an H2S emergency which would be tragic if they were above a leak with an upward velocity or they ran down-wind towards higher ground.

Bob - January 2007 bob@optimaepc.fsnet.co.uk (By the way I'm English but have no problem with American spellings) —The preceding unsigned comment was added by 90.240.197.87 (talk) 13:40, 22 January 2007 (UTC).

I see your concerns. First I want to stress, safety sections should be kept to a minimum (per WP:NOT, not a manual/not a safety guard). But well, that does not mean that what is written there should not be correct. Could you give it a try to rewrite the section, I think it should be kept to 3-4 sentences, stating the typical dangers, for the rest people will have to find a MSDS (direct external links are better avoided for bias-reasons)? Cheers! --Dirk Beetstra T C 13:35, 26 January 2007 (UTC)

[edit] HTML code?

Anyone want to fix the mess that is this page? I would myself but am still just getting used to wiki's particular ways of interpreting code.

[edit] Need to update the odor threshold in the Tox section

Based on the information available on the odor threshold for H2S, I don't think that the odor recognition value listed in this entry is a value that is rigorously supported in the literature. It also fails to convey the significant variability of H2S odor thresholds. The reference cited in this entry is based on a table from a 1978 document from the Water Environment Federation, and as far as I can tell it is the only reference that gives a recognition threshold of 0.00047 ppm for H2S. Also, this specific 1978 document is not readily available, so it is difficult to track down the study or studies on which this value was based.

In 2006, the CDC's Agency for Toxic Substances and Disease Registry published a toxicological profile for H2S that provides an updated and more realistic statement on the variability of the odor threshold of H2S as it is represented in the literature (http://www.atsdr.cdc.gov/toxprofiles/tp114.html). On page 129 of 253 of this document they state:

"The odor threshold for hydrogen sulfide is variable and various ranges have been reported. Ruth (1986) reviewed odor thresholds of several hundred chemicals, including hydrogen sulfide, from the industrial hygiene literature and other compilations of odor threshold data; an odor threshold range of 0.0005–0.010 ppm was reported. Guidotti (1994) reported an odor threshold range of 0.01–0.3 ppm. Since high concentrations of hydrogen sulfide (150 ppm) can paralyze the olfactory nerve, odor may not be a reliable indicator of the presence of this gas (HSDB 2006)."

Furthermore, the American Industrial Hygiene Association has published a list of critiqued odor detection threshold values for a vast number of substances, including H2S (Table 5.1, pg. 20 of "Odor Thresholds for Chemicals with Established Occupational Health Standards." Copyright 1989 by the AIHA). They list the range of all referenced values to be 0.00007 - 1.4 ppm, with a range of acceptable values based on their critique to be 0.001 - 0.13 ppm. The current value and citation in this entry for the odor recognition threshold of H2S should be replaced with either of the AIHA ranges for H2S odor detection limit thresholds listed above, followed by a comment on the significant variability that has been reported. —Preceding unsigned comment added by Jurban48 (talk • contribs) 17:46, 11 December 2007 (UTC)

[edit] Hydrogen sulfide as a hybernation inducing agent

http://www.lewrockwell.com/sardi/sardi78.html VTNC (talk) 15:56, 12 December 2007 (UTC)

[edit] Suicide

I cannot understand why it should be described in detail how to commit suicide with it, so I deleted it. I hope you agree.Mycomp 13:58, 14 May 2008 (UTC)

Thank you for protecting me from myself. I came here as a supermarket manager looking for the ingredients that others may be purchasing to use, and what to watch out for, but obviously the censorship police have beat me to the punch.

What products are people using to make this? —Preceding unsigned comment added by 210.153.95.1 (talk) 04:12, 19 May 2008 (UTC)

[edit] Does it Float?

If you had a container with both liquied and solid forms of this chemical, would the solid form float on the liquid form like the similar H2O solids and liquids do? Jason Harvestdancer | Talk to me 15:10, 5 June 2008 (UTC)

This depends on the densities of liquid and solid hydrogen sulfide. If the solid is denser than the liquid, the solid will sink.
The density of liquid H2S is 914.9 kg m−3, according to Air Liquide. This paper gives the density of solid H2S as around 1.1 g cm−3 (1100 kg m−3). Based on this information, solid hydrogen sulfide will not float on the less dense liquid.
See also this site full of explanations and references.
Ben (talk) 15:46, 5 June 2008 (UTC)