Wiki: Acid

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NT
==Precautions=Most acids are high risk chemicals. Several precautions are advisable with the stronger acids. These don't all apply to vinegar & citric acid. * When diluting, never add water to acid, always add acid to water. Doing so is sometimes highly exothermic, and should be done a bit at a time, wearing safety specs. If done the wrong way the result can even progress to explosion sometimes. Exploding boiling acid is not an essential nutrient. * The stronger acids used in DIY can eat through skin rapidly. Wear suitable gloves * When holding hold the bottle by the label area, so any unnoticed runs are on the same side, and that's not where you're holding it. * Don't mix acid with bleach, the resulting chlorine is quite toxic. * Don't mix acid with alkalis, excess heat is generated, and boiling spitting acid isn't usually a good thing. * Strong acid plus metal can generate hydrogen, which is explosive at above 4% concentration. * Suitable gloves & eye protection are sensible for the stronger acids. * In case of skin contact with strong acids, wash for 10 minutes to minimise burning, chemical reaction & contamination. In case of eye contact, wash well and seek medical help promptly.
==Hydrochloric Acid=[[image:HCl 34% 4168-3.jpg|right|200px]] * The strongest of all the acids used in DIY * Also known as spirits of salt, muriatic acid
Uses * Eats cement & lime * Cleans cement off bricks etc - but not off cement products * Can also be used to descale ceramics, but can discolour otherwise unnoticeable surface cracking 18% hydrochoric acid is used industrially to clean steel before coating ('pickling'). Spent pickling solution is sometimes then used as ferrous chloride.
Risks * Destroys cement joints in ceramic pipes * Strong HCl produces choking fumes and mist * HCl is highly corrosive to skin, eyes, lungs etc, and toxic. Inhalation of ttoo much of the fumes can cause death * In case of skin contact, wash for 10-15 minutes. In case of eye contact, wash for 10-15 minutes, lifting both upper & lower eyelids regularly, and seek medical advice without delay. * Incompatible with many substances * [http://grover.mirc.gatech.edu/data/msds/50.html MSDS]
Purchase * Sold as brick acid, drain unblocker, and is a component of many patio cleaners. * Available upto 34%
==Sulphuric Acid=[[image:H2SO4 98% 4170-3.JPG|right|200px]] Sulphuric acid has many names, including vitriol, glover acid, tower acid, fertiliser acid, chamber acid, battery acid, dipping acid, mattling acid, electrolyte acid.
Uses * Eats organic materials rapidly. Eats paper etc in seconds. * Good for drains where the blockage is organic * Density of 1.84 means it sinks to the bottom of blockages * Lead acid batteries use high purity sulphuric acid of around 4M. Less pure drain cleaning acid is not usable for batteries. * Strong desiccant * Reaction with sugar produces carbon * Reaction of hot strong H2SO4 with copper produces copper sulphate, a mould inhibiting antimicrobial. * Reaction with zinc produces zinc sulphate, a mould inhibiting antimicrobial. * Used industrially to remove rust
Risks * Dangerous to skin & eyes * Destroys cement joints in ceramic pipes * Toxic * Strong sulphuric acid can react violently with water * In work situations all use of sulphuric acid must be assessed under the COSHH regulations. * [http://msds.chem.ox.ac.uk/SU/sulfuric_acid_concentrated.html MSDS]
Purchase * Upto 98% sulphuric acid is available as drain unblocker.
==Sulphamic Acid=Also known as sulfamic acid, amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid
Uses * Used to descale heat exchangers in heating systems * Descale and clean metals and ceramics * A component in some household descalers & denture tablets
Risks * Lower risk than hydrochloric acid
Purchase * Fernox DS-3 contains sulphamic acid, inhibitors, indicators & surfactant.
==Phospohoric Acid=Uses * Used as rust remover. Turns rust into a stable black ferric phosphate. Often used as a gel preparation to enable it to cling to surfaces at all angles. * Phospohoric acid is used as a food additive, E338. * Sometimes used to remove limescale and cement stains. * Sometimes used as a soldering flux
Risks: * Don't permit contact with bleach, ammonia or metals * [http://www.cdc.gov/niosh/npg/npgd0506.html Safety data]
Purchase * Sold in preparations known as rust convertor, rust remover, rust killer, naval jelly.
=etic Acid=[[image:Acetic acid 4159-4.JPG|right|200px]]
* Also known as ethanoic acid, acetyl hydroxide (AcOH), hydrogen acetate (HAc), ethylic acid, methanecarboxylic acid * Concentrated acetic acid is called glacial acetic acid. It freezes at 16C. * Acetic acid has a characteristic powerful vinegary smell.
Uses * Sometimes used with other acids as a descaler * Food additive E260 * Vinegar is primarily dilute acetic acid, typically around 4-8% * Vinegar cleans copper, copper alloys, brass, bronze - the runoff is toxic * Diluted vinegar cleans glass & helps avoid smearing * Glacial acetic acid is used to remove warts & verrucas, and the dilute acid for ear infections. * Acetic acid makes copper acetate, a pigment and fungicide.
Risks * Acetic acid is corrosive, and at high strengths highly flammable. * Overexposure to the fumes can cause difficulty breathing. This can easily happen at room temperature. * Symptoms of exposure can be delayed for a few hours. * Fumes above 39C can be explosive * Latex gloves don't protect against acetic acid, use nitrile ruber gloves. * [http://www.inchem.org/documents/icsc/icsc/eics0363.htm Safety info]
==Citric Acid=* A weak edible acid
Uses * Citric acid is a widely used food additive, E330 * Descaler for appliances that can't use stronger acids, eg kettles, washing machines etc. * 2% citric acid makes a handy scale tackling bathroom cleaner. 6% can remove scale without rubbing Salt enhances the descaling action of citric to an extent. * Appliance descalers in supermarkets are usually citric acid based, and a pricey way to buy the stuff. * Citric acid can often substitute for lemon juice in recipes
Purchase * Citric acid is sold as a bagged food additive in some foreign food supermarkets, or less cheaply in small boxes at pharmacies (much used by heroin users). * Irritant to skin & eyes. In case of eye contact, wash well for 10 minutes and seek medical assistance * Corrodes copper, zinc, aluminium and their alloys * [http://www.coastalscents.com/cfwebstore/index.cfm ? fuseactionature.display&feature_id!7 MSDS]
==See Also=
[[Category:Cleaning]] [[Category:Chemicals]]
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Tabby wrote:

You need to draw the distinction between "strong" and "concentrated". You have a number of times used the adjective "strong" when you should have used "concentrated"
Hydrochloric acid is of comparable strength as sulphuric acid, but you can get sulphuric acid at 98% concentration, whereas, you rarely get hydrochloric acid at above 50% concentration in a DIY situation. So, although your assertion that hydrochloric acid is "the strongest of all the acids used in DIY", is true, it is neither the most concentrated nor arguably the most dangerous. I would certainly be more wary of sulphuric acid than hydrochloric acid.
Hydrochloric acid is stomach acid and if you don't have any open wounds you could happily wash your hands in a moderately concentrated solution of it. Sulphuric acid is corrosive and dangerous to your skin and eyes at almost any useful concentration.
More importantly, hydrofluoric acid (which is a weak acid and may possibly be encountered in DIY situations) is, on the whole, very much more dangerous than sulphuric acid as it is extremely corrosive to organics, metals and glass.
You should also be clear whether concentrations cited as a percentage are v/v, w/v or w/w.
http://en.wikipedia.org/wiki/Strong_acid
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Also, never add sulphuric acid to water, always the other way round!
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wrote:

You got that wrong. Acid to water. Always.
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It was right in my head but I reversed "always" and "never" when I typed. Sorry!
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Bob Martin wrote:

The traditional rhyme might have an annoying American tinge, but it's difficult to remember it the wrong way round ...
"Do as you oughta, add acid to water"
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On 14/08/2010 08:05, Andy Burns wrote:

Can't help thinking the whole thing is a non-starter in a d-i-y context
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stuart noble wrote:

Do schoolkids actually get to *do* chemistry thesedays, or just watch youtube clips of glowing splints being inserted into boiling tubes of potassium chlorate?
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On Sat, 14 Aug 2010 09:53:07 +0100, Andy Burns

Yes.
--
(\__/) M.
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Death by dyslexia
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geoff

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I can't believe those 98% drain cleaners are still on sale. Horrible stuff, and unexpectedly heavy when you pick the container up for the first time
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hcl max is around 30odd%. Pure hcl is a gas
So, although your assertion that hydrochloric acid is "the strongest of all the acids used in DIY", is true, it is neither the most concentrated nor arguably the most dangerous. I would certainly be more wary of sulphuric acid than hydrochloric acid.

--
Tim Watts

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On 13/08/10 00:23, Dave Osborne wrote:

Technically Hydrochloric acid is a stronger acid that sulphuric but that's only of academic interest. Sulphuric acid is far more dangerous so in colloquial English it's stronger.

Hydrofluoric acid is used to etch glass. It's particularly dangerous because it attacks the skin and the resulting burns take far longer to heal than other types of burn.
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Bernard Peek
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I really think you are wrong there, skin burns are the least of your worries ...
"Hydrofluoric acid is an extremely corrosive liquid and is a contact poison. It should be handled with extreme care, beyond that accorded to other mineral acids. Owing to its low dissociation constant, HF penetrates tissue more quickly than typical acids. Because of the ability of hydrofluoric acid to penetrate tissue, poisoning can occur readily through exposure of skin or eyes, or when inhaled or swallowed. Symptoms of exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function, meaning that burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury.[8]
Once absorbed into blood through the skin, it reacts with blood calcium and may cause cardiac arrest. Burns with areas larger than 25 square inches (160 cm2) have the potential to cause serious systemic toxicity from interference with blood and tissue calcium levels.[9] In the body, hydrofluoric acid reacts with the ubiquitous biologically important ions Ca2+ and Mg2+. Formation of insoluble calcium fluoride is proposed as the etiology for both precipitous fall in serum calcium and the severe pain associated with tissue toxicity.[10] In some cases, exposures can lead to hypocalcemia. Thus, hydrofluoric acid exposure is often treated with calcium gluconate, a source of Ca2+ that sequesters the fluoride ions. HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel[11][12][13] or special rinsing solutions.[14][15] However, because it is absorbed, medical treatment is necessary;[9] rinsing off is not enough. In some cases, amputation may be required"
--
geoff

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SNIP
You seem to have happily mixed technically correct content with some personal opinions. Wouldn't it have been simpler to list a series of internet links to chemical properties and hazchem precautions from existing industry websites?
Having extensively worked with some seriously hazardous chemicals such as Hydrochloric, Sulphuric, Citric, Hydrofluoric, Acetic Anhydride and a number of other acids plus Potassium Hydroxide, Sodium Hydroxide Sodium Hypochlorite (Bleach) and exotic Organic compounds at industrial bulk delivery concentrations in the food process industry, I think their handling is best carried out under controlled conditions using appropriate protective equipment. The appropriate instructions are invariably made available by the suppliers or manufacturers (often on the labels of the packaging). Note that hydrofluoric acid dissolves glass and is used extensively in the horticultural undustry to clean greenhouses. Contact with human tissue is very dangerous but still it goes on. Phosphoric acid is also extensively used as a nutrient component for irrigated glasshouse crops such as cucumbers and tomatoes. If the public knew what went on in producing some popular foods and household products the sales would collapse overnight.
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ooo you tease! go on then shock me....
Jim K
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should you include Nitric & Picric ?
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On 13/08/10 15:28, Rick Hughes wrote:

Nitric isn't common but it's nasty. Concentrated it produces poisonous and corrosive fumes. It attacks metals and organic matter and can cause fires.
Picric is used as a topical antiseptic. It's mostly harmless in dilute solution, explosive when dry. If a solution is exposed to light it can throw down a solid precipitate which is explosive and shock-sensitive.
While we're about it, how about Chromic. Occasionally used for really extreme cleaning applications. It's a mixture of chromate salts and sulphuric acid. It's extremely corrosive and is an oxidant that can set fire to organic materials like paper and skin.
--
Bernard Peek
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--

The only safe advice for the DIYer on chromic is don't have anything to do with it. You cannot deal with the waste even if you can keep the stuff off your skin. I used to test a chromating tank and advise on any chemical additions that might be necessary. I wore a rubber mask, visor, and rubber gauntlets up to my elbows. We had separate tanks for waste disposal, but one day a charge hand rinsed his gloves in the sink. We later had a visit from a very irate water board official... chromium is one thing they definitely do not want down at the sewage works.
S
S
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Tabby wrote:

Would a simple explanation of the ph scale help?
--
Dave - The Medway Handyman
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