:For alternative meanings see acid (disambiguation).
An acid (represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. An acid always has a pH of less than 7. It is a molecule or ion that contains hydrogen or that is able to give up a proton to a base, or accept an unshared pair of electrons from a base. An acid reacts with a base in a neutralization reaction to form a salt.
1 Chemical characteristics
In water, there is the following reaction:
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There is a distinction between weak acids and strong acids. For a strong acid, no AH remains in solution:
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That is why the acidity constant is only defined for weak acids:
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Some of the stronger acids include the hydrohalic acids - HCl, HBr, and HI - and the oxyacids, which tend to contain central atoms in high oxidation states surrounded by oxygen - including HNO3, H2SO4, HClO4.
Acidic (chemistry), the opposite to basic, reacting with basics to form salts.
Acidic (geology), of rock: containing more than 65% of silica.
2 Characteristics
Acids are generally:
- Taste: sour when dissolved in water
- Touch: strong acids have a stinging feeling
- Reactivity: acids react violently with many metals
- Electrical conductivity: acids are electrolytes
3 Acids in food
- acetic acid or ethanoic acid: (E260) found in vinegarVinegar (from Old French vinaigre "sour wine") is a sour liquid made from the oxidation of ethanol in wine, cider, beer, or the like. Vinegar is typically three to five percent by volume acetic acid, and natural vinegars also contain smaller amounts of ta and tomato sauce
- adipic acid : (E355)
- alginic acid : (E400)
- benzoic acidStructural formula Benzoic acid CHC(O)OH, is an aromatic carboxylic acid. Benzoic acid is used as a food preservative and occurs naturally in certain plants. For example, it is a major component of gum benzoin, which in turn is a major component of the ty: (E210)
- boric acidProperties General Name Boric acid Chemical formula H B O Appearance White solid Physical Formula weight 61. 8 amu Melting point Decomposes at 442 K (169 °C) Density 1. 4 ×103 kg/ m3 Crystal structure ? Solubility 5. 7 g in 100g water Thermochemistry &Del: (E284)
- ascorbic acidL-Ascorbic acid Chemical name2-oxo-L-threo-hexono-1,4-lactone-2,3-enediol or R -3,4-dihydroxy-5-( R -1,2-dihydroxyethyl)furan-2(5''H -one Chemical formulaCHO Molecular mass176. 12 g/mol Melting point190 192 °C CAS number50-81-7 SMILESOC1 C(C(O[C@@H]1[C@@H(vitamin C): (E300) found in fruits
- citric acidProperties General Name Citric acid Chemical formula C H O Formula weight 192. 13 amu Synonyms 2-hydroxy-1,2,3-propanetricarboxylic acid CAS number 77-92-9 Phase behavior Melting point 426 K (153 °C) Thermal decomposition temperature 448 K (175°C) Acid-ba: (E330) found in citrus fruits
- carbonic acidProperties General Name Carbonic acid Chemical formula H C O Carbonic acid is a weak acid with the chemical formula of H C O. It is the reaction product of water and carbon dioxide and exists in an equilibrium with water and carbon dioxide whenever the la: (E290) found in carbonated beverages
- carminic acid : (E120)
- cyclamic acid : (E952)
- erythorbic acid : (E315)
- erythorbin acid : (E317)
- formic acid: (E236)
- fumaric acid: (E297)
- gluconic acid : (E574)
- glutamic acid: (E620)
- guanylic acid : (E626)
- hydrochloric acid: (E507)
- inosinic acid : (E630)
- lactic acid: (E270) found in dairy products such as yoghurt and sour milk
- malic acid: (E296)
- metatartaric acid : (E353)
- nicotinic acid: (E375)
- pectic acid: found in fruits and some vegetables
- phosphoric acid: (E338)
- propionic acid: (E280)
- sorbic acid: (E200) found in foods and drinks
- stearic acid: (E570)
- succinic acid: (E363)
- sulfuric acid: (E513)
- tannic acid: found in tea
- tartaric acid: (E334) found in grapes
- oxalic acid: found in spinach and rhubarb
