==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 ? fuseactionþature.display&feature_id!7 MSDS]