Talk:Nitric acid

From Wikipedia, the free encyclopedia

	Chemistry Portal Nitric acid is within the scope of WikiProject Chemicals, a daughter project of WikiProject Chemistry, which aims to improve Wikipedia's coverage of chemicals. To participate, help improve this article or visit the project page for details on the project.
Core	This is a core article in the WikiProject Chemicals worklist
B	This article has been rated as B-Class on the quality scale.
High	This article has been rated as High-importance on the importance scale.
Article Grading: The article has been rated for quality and/or importance but has no comments yet. If appropriate, please review the article and then leave comments here to identify the strengths and weaknesses of the article and what work it will need.

Contents 1 Corrosive hazard 2 Preparation 3 NFPA diamond 4 Molar mass 5 Nitric acid and Egyptians 6 Nitric acid properties 7 pKa 8 Cncentration of Nitric Acid 9 formula

[edit] Corrosive hazard

I don't understand the comments about yellow/orange stains: doesn't this acid actually burn skin and corrode it, rather than stain it??? This needs to be clarified, because as written, the article is self-contradicting. Nyh 09:02, 31 Mar 2004 (UTC)

From my experience, the acid burns and stains the skin, and the stain persists long after the burn is healed. Additionally, concentrations that are generally too dilute to burn the skin do result in yellow stains. Gentgeen 14:07, 31 Mar 2004 (UTC)

ADDENDUM-I found an MSDS here that lists under potential health effects, Skin Contact: Corrosive! Can cause redness, pain, and severe skin burns. Concentrated solutions cause deep ulcers and stain skin a yellow or yellow-brown color. Gentgeen 16:56, 31 Mar 2004 (UTC)

How long does the staining last for? Should I be worried about anything more than cosmetics? 169.237.44.114 21:35, 21 February 2006 (UTC)

For "normal" cases, those in which there is no actual chemical burn, the stain lasts for five to seven days. It is caused by the oxidation of tyrosine residues in the proteins which make up the epidermis—the same reaction which causes cut apples to turn brown—and so lasts until that layer of the epidermis is shed naturally. The stained epidermis tends to disappear faster than unstained epidermis, but it is rarely so fast as to cause sensitivity or the underlying skin. Minor staining of the fingers is considered inocuous. I tell my students to go and see their doctor if they are worried, as medical students do some chemistry during their studies (and they're not usually the best) and so many doctors have personal experience of minor nitric acid stains (I explain the second part as well). To my knowledge, not one student has yet bothered! Physchim62 (talk) 22:26, 21 February 2006 (UTC)

[edit] Preparation

Hi guys, could you elaborate more on the first method of synthesis, where it says "by taking a **** on someones face"?

About the synthesis, it says to convert red to white by using reduced air pressure, giving the values of 27 KPa or 20 mmHg. These are diffrent values by a factor of ten; I'm going to assume it's the higher one (just my intuitive guess) and change it to 27Kpa and 200mmHg. I could be wrong though, does anyone know for sure?--2tothe4 01:29, 12 November 2005 (UTC)

Something else... the removal of the NO by reduced pressure makes sense, but wouldn't heating the acid have the same effect? Or would the HNO3 start to dissociate?--2tothe4 14:51, 12 November 2005 (UTC)

It does indeed dissociate as you heat it, defeating the purpose. On the other hand, there was talk of reducing the temperature of the reaction (from 90 C to 81-85 C) which would significantly reduce the amount of NO. --AK7 13:42, 24 November 2005 (UTC)

Doesnt sulfuric acid turn skin yellow as well?

[edit] NFPA diamond

The NFPA symbol (i think thats the right terminology) is wrong. Health is 4 and reactivity is 3.

The values for the NFPA diamond come from the International Chemical Safety Card cited in the article. Physchim62 (talk) 09:49, 7 January 2006 (UTC)

[edit] Molar mass

What is that "g" after the digit 9 in the molar mass 63.0129g g/mol? Was it a typing error? sentausa 18:02, 9 March 2006 (UTC)

Almost certainly, yes, or a copy-and-paste edit. I've removed it now, and rounded the figure to the first two decimal places (as is usual for general-purpose molar masses). Physchim62 (talk) 17:42, 10 March 2006 (UTC)

[edit] Nitric acid and Egyptians

I removed the statement about nitric acid being used by the ancient Egyptians; it seems dubious and is not backed up by a given external source. Can anyone find a source for that statement? Algebra 00:37, 6 December 2006 (UTC)

[edit] Nitric acid properties

The properties of HNO₃ are still too vague. Should we add some reactions as illustration for each property?_AbelinCAusesobad 14:00, 20 December 2006 (UTC)

[edit] pKa

I'm confused with the pKa of nitric.

• -1.3 here

• -1.44 here

• -1.5 here

And I can't find where there has the value -2.

Which one is true?

Any pK_a which is so low is difficult (if not impossible) to measure accurately. I'm frankly amazed that you found three values so close, as I see have seen values as low as −3! About −1.5 seems reasonable given your sources; you won't find much better. Physchim62 (talk) 17:04, 18 January 2007 (UTC)

Is the relation of pKa to the actual Ka value goes like: pKa = -logKa ? Because I'm looking for an actual value of Ka not pKa. Therefore, I think that noting the Ka value of all chemicals in the article table is of some importance, no? 74.96.186.207 00:46, 21 January 2007 (UTC)

Actually, I found that doing pKa = -logKa on a pka value of negative (such as -2, -1.5 noted above) impossible. I am also looking for Ka and Kb values and support the fact that such values should be noted on the main article - Anonymous Chemist

Yes, it's the same as pH = -lg[H⁺]. Causesobad --> Talk) 13:13, 22 January 2007 (UTC)

[edit] Cncentration of Nitric Acid

Can i concentrate the Nitric acid like H2S04? If not then how can concentrate the Nitric Acid? —The preceding unsigned comment was added by 193.251.135.126 (talk) 12:45, 28 January 2007 (UTC).

[edit] formula

what is the formula for nitric acid in acid rain??? O~O —The preceding unsigned comment was added by 86.6.160.152 (talk) 16:01, 19 February 2007 (UTC).