News tagged with acid

How does DPP-4 inhibition affect liver function?

(HealthDay)—Dipeptidyl peptidase-4 (DPP-4) inhibition may attenuate hepatic steatosis and insulin resistance induced by the Western diet (WD) through hepatic lipid remodeling and modulation of hepatic mitochondrial ...

Jan 27, 2015
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A challenge to expedite Genervon's new ASL drug

(Medical Xpress)—The Ice Bucket Challenge to raise awareness for Amyotrophic lateral sclerosis (ALS) went viral on social media last summer. Over 1.2 million videos were posted on Facebook alone. The difficulty ...

Jan 27, 2015
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Generic form of nexium approved

(HealthDay)—The first generic version of the heartburn drug Nexium (esomeprazole) has been approved by the U.S. Food and Drug Administration.

Jan 26, 2015
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Progress in diabetes drug delivery

A drug therapy for diabetes treatment is being developed by an international research team led by WA scientists, which combines an existing anti-diabetic drug with bile acids to improve the drug's delivery ...

Jan 22, 2015
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Acid

An acid (from the Latin acidus/acēre meaning sour) is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red. Chemicals or substances having the property of an acid are said to be acidic.

Common examples of acids include acetic acid (in vinegar), sulfuric acid (used in car batteries), and tartaric acid (used in baking). As these three examples show, acids can be solutions, liquids, or solids. Gases such as hydrogen chloride can be acids as well. Strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid.

There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition. The Arrhenius definition states that acids are substances which increase the concentration of hydronium ions (H3O+) in solution. The Brønsted-Lowry definition is an expansion: an acid is a substance which can act as a proton donor. Most acids encountered in everyday life are aqueous solutions, or can be dissolved in water, and these two definitions are most relevant. The reason why pHs of acids are less than 7 is that the concentration of hydronium ions is greater than 10−7 moles per liter. Since pH is defined as the negative logarithm of the concentration of hydronium ions, acids thus have pHs of less than 7. By the Brønsted-Lowry definition, any compound which can easily be deprotonated can be considered an acid. Examples include alcohols and amines which contain O-H or N-H fragments.

In chemistry, the Lewis definition of acidity is frequently encountered. Lewis acids are electron-pair acceptors. Examples of Lewis acids include all metal cations, and electron-deficient molecules such as boron trifluoride and aluminium trichloride. Hydronium ions are acids according to all three definitions. Interestingly, although alcohols and amines can be Brønsted-Lowry acids as mentioned above, they can also function as Lewis bases due to the lone pairs of electrons on their oxygen and nitrogen atoms.

This text uses material from Wikipedia licensed under CC BY-SA