==Precautions=Most acids are high risk chemicals. Several precautions are advisable
with the stronger acids. These don't all apply to vinegar & citric
* 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
The stronger acids used in DIY can eat through skin rapidly. Wear
* 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
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
* 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.
* 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
* Sold as brick acid, drain unblocker, and is a component of many
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.
* 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
* Used industrially to remove rust
* Dangerous to skin & eyes
Destroys cement joints in ceramic pipes
Strong sulphuric acid can react violently with water
* In work situations all use of sulphuric acid must be assessed under
the COSHH regulations.
* 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
* Used to descale heat exchangers in heating systems
Descale and clean metals and ceramics
* A component in some household descalers & denture tablets
* Lower risk than hydrochloric acid
* Fernox DS-3 contains sulphamic acid, inhibitors, indicators &
* 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
* Don't permit contact with bleach, ammonia or metals
[http://www.cdc.gov/niosh/npg/npgd0506.html Safety data]
* 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
* Acetic acid has a characteristic powerful vinegary smell.
* 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
* 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.
* 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
[http://www.inchem.org/documents/icsc/icsc/eics0363.htm Safety info]
==Citric Acid=* A weak edible acid
* 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
* 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