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==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/sulfuri...centrated.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.


==Acetic 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?
fuseaction=feature.display&feature_id=217 MSDS]


==See Also==


[[Category:Cleaning]]
[[Category:Chemicals]]