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Dissociation of sodium chloride in water

This figure shows a crystal lattice of sodium chloride interacting with water to form a hydrated sodium ion and a hydrated chloride ion.
Notice that the crystals of sodium chloride dissociate not into molecules of NaCl, but into Na + cations and Cl anions, each completely surrounded by water molecules.

Many other salts are important in the body. For example, bile salts produced by the liver help break apart dietary fats, and calcium phosphate salts form the mineral portion of teeth and bones.

Acids and bases

Acids and bases, like salts, dissociate in water into electrolytes. Acids and bases can very much change the properties of the solutions in which they are dissolved.

Acids

An acid    is a substance that releases hydrogen ions (H + ) in solution ( [link] a ). Because an atom of hydrogen has just one proton and one electron, a positively charged hydrogen ion is simply a proton. This solitary proton is highly likely to participate in chemical reactions. Strong acids are compounds that release all of their H + in solution; that is, they ionize completely. Hydrochloric acid (HCl), which is released from cells in the lining of the stomach, is a strong acid because it releases all of its H + in the stomach’s watery environment. This strong acid aids in digestion and kills ingested microbes. Weak acids do not ionize completely; that is, some of their hydrogen ions remain bonded within a compound in solution. An example of a weak acid is vinegar, or acetic acid; it is called acetate after it gives up a proton.

Acids and bases

This figure shows four beakers containing different liquids.
(a) In aqueous solution, an acid dissociates into hydrogen ions (H + ) and anions. Nearly every molecule of a strong acid dissociates, producing a high concentration of H + . (b) In aqueous solution, a base dissociates into hydroxyl ions (OH ) and cations. Nearly every molecule of a strong base dissociates, producing a high concentration of OH .

Bases

A base    is a substance that releases hydroxyl ions (OH ) in solution, or one that accepts H + already present in solution (see [link] b ). The hydroxyl ions (also known as hydroxide ions) or other basic substances combine with H + present to form a water molecule, thereby removing H + and reducing the solution’s acidity. Strong bases release most or all of their hydroxyl ions; weak bases release only some hydroxyl ions or absorb only a few H + . Food mixed with hydrochloric acid from the stomach would burn the small intestine, the next portion of the digestive tract after the stomach, if it were not for the release of bicarbonate (HCO 3 ), a weak base that attracts H + . Bicarbonate accepts some of the H + protons, thereby reducing the acidity of the solution.

The concept of ph

The relative acidity or alkalinity of a solution can be indicated by its pH. A solution’s pH    is the negative, base-10 logarithm of the hydrogen ion (H + ) concentration of the solution. As an example, a pH 4 solution has an H + concentration that is ten times greater than that of a pH 5 solution. That is, a solution with a pH of 4 is ten times more acidic than a solution with a pH of 5. The concept of pH will begin to make more sense when you study the pH scale, like that shown in [link] . The scale consists of a series of increments ranging from 0 to 14. A solution with a pH of 7 is considered neutral—neither acidic nor basic. Pure water has a pH of 7. The lower the number below 7, the more acidic the solution, or the greater the concentration of H + . The concentration of hydrogen ions at each pH value is 10 times different than the next pH. For instance, a pH value of 4 corresponds to a proton concentration of 10 –4 M, or 0.0001M, while a pH value of 5 corresponds to a proton concentration of 10 –5 M, or 0.00001M. The higher the number above 7, the more basic (alkaline) the solution, or the lower the concentration of H + . Human urine, for example, is ten times more acidic than pure water, and HCl is 10,000,000 times more acidic than water.

Questions & Answers

what is the difference between basal laminal and basal membrane
Nartey Reply
If one is missing the opsin which detects wavelengths of approximately 560 nm what color would they be unable to see?
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Sir Reply
Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelialcell: squamous, columnar, and cub
DJ
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Sir
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Sir
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nitesha Reply
Cerebrospinal fluid is a clear, colorless body fluid found in the brain and spinal cord. It is produced by the specialised ependymal cells in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations.
DJ
cerebrospinal fluid is the fluid present in the brain and spinal cord
olusoga
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olusoga
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to transport oxygen in hemoglobin and nutrients
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Sheika Reply
thoracic pump for blood, and lymphatic flow for mucus membranes .
Rugiatu
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Maulidi Reply
the human body is the entire structure of a human being.it is composed of many different types of cells that together create tissues and subsequently organ systems.they ensure homeostasis and viability of the human body
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Carine Reply
skin
Vinod
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smallest basic unit of life
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cell
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different kinds of sutures and their functions...
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gross anatomy is the study of what you can observe of the human body without a microscope.
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patella
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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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