Acid vs. Alkali — What's the Difference?

An acid is a molecule or ion capable of either donating a proton (i.e., hydrogen ion, H+), known as a Brønsted–Lowry acid, or, capable of forming a covalent bond with an electron pair, known as a Lewis acid.The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids.

In chemistry, an alkali (; from Arabic: القلوي‎ al-qaly "ashes of the saltwort") is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water.

A substance with particular chemical properties including turning litmus red, neutralizing alkalis, and dissolving some metals; typically, a corrosive or sour-tasting liquid of this kind.

A compound with particular chemical properties including turning litmus blue and neutralizing or effervescing with acids; typically, a caustic or corrosive substance of this kind such as lime or soda

A molecule or other species which can donate a proton or accept an electron pair in reactions.

A carbonate or hydroxide of an alkali metal, the aqueous solution of which is bitter, slippery, caustic, and characteristically basic in reactions.

The drug LSD

Any of various soluble mineral salts found in natural water and arid soils.

Containing acid or having the properties of an acid; having a pH of less than 7.

Alkali metal.

Sharp-tasting or sour

A substance having highly basic properties; a strong base.

(of rock, especially lava) containing a relatively high proportion of silica

(chemistry) One of a class of caustic bases, such as soda, soda ash, caustic soda, potash, ammonia, and lithia, whose distinguishing characteristics are dissolving in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue.

Any of a class of substances whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals to form salts.

(Western United States) Soluble mineral matter, other than common salt, contained in soils of natural waters.

A substance that yields hydrogen ions when dissolved in water.

Soda ash; caustic soda, caustic potash, etc.

A substance that can act as a proton donor.

One of a class of caustic bases, such as soda, potash, ammonia, and lithia, whose distinguishing peculiarities are solubility in alcohol and water, uniting with oils and fats to form soap, neutralizing and forming salts with acids, turning to brown several vegetable yellows, and changing reddened litmus to blue.

A substance that can accept a pair of electrons to form a covalent bond.

Soluble mineral matter, other than common salt, contained in soils of natural waters.

A substance having a sour taste.

Any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water;

The quality of being sarcastic, bitter, or scornful

A mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture

(Slang) See LSD1.

Of, relating to, or containing an acid.

Having a high concentration of acid.

Having the characteristics of an acid.

Having a pH of less than 7.

Having a relatively high concentration of hydrogen ions.

(Geology) Containing a large proportion of silica

Having a sour taste.

Biting, sarcastic, or scornful

Sour, sharp, or biting to the taste; tart; having the taste of vinegar.

(figuratively) Sour-tempered.

Of or pertaining to an acid; acidic.

(music) Denoting a musical genre that is a distortion (as if hallucinogenic) of an existing genre, as in acid house, acid jazz, acid rock.

A sour substance.

(chemistry)

Any compound which yields H+ ions (protons) when dissolved in water; an Arrhenius acid.

Any compound that easily donates protons to a base; a Brønsted acid.

Any compound that can accept a pair of electrons to form a covalent bond; a Lewis acid.

Any corrosive substance.

LSD, lysergic acid diethylamide.

Sour, sharp, or biting to the taste; tart; having the taste of vinegar: as, acid fruits or liquors. Also fig.: Sour-tempered.

Of or pertaining to an acid; as, acid reaction.

A sour substance.

One of a class of compounds, generally but not always distinguished by their sour taste, solubility in water, and reddening of vegetable blue or violet colors. They are also characterized by the power of destroying the distinctive properties of alkalies or bases, combining with them to form salts, at the same time losing their own peculiar properties. They all contain hydrogen, united with a more negative element or radical, either alone, or more generally with oxygen, and take their names from this negative element or radical. Those which contain no oxygen are sometimes called hydracids in distinction from the others which are called oxygen acids or oxacids.

Any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt

Street name for lysergic acid diethylamide

Harsh or corrosive in tone;

Containing acid;