Sodium Chloride

NaCl

Sodium chloride is the most common salt, the common table salt used for the seasoning of food. It forms in cubic crystals apparent even in table salt. It occurs commonly in the mineral form, halite, also called rocksalt. It can be formed by the acid-base reaction of hydrochloric acid and sodium hydroxide:

As a solid, sodium chloride is crystalline and forms a cubic lattice. The bonding of the sodium and chlorine atoms is one of the classic examples of ionic bonding. In aqueous solution it ionizes to Na+ and Cl- ions and forms an electrically conducting solution.


Ordinary table salt, 50x
The ionic bonding of NaCl can be visualized in terms of Lewis diagrams.

When the diameters of sodium and chlorine and their ions are measured, they offer some confirmation of the picture of ionic bonding.

When sodium loses an electron to form Na+, its effective size decreases to about half. When chlorine gains an electron to produce the octet structure Cl-, its size increases to almost double (Shipman, et al).

Sodium chloride exists on the earth in great abundance in sea water and is an important part of the fluid electrolytes of humans and other living organisms.

NaCl Bond Details


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Reference
Shipman, Wilson and Todd
Ch 12
 
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Sodium Bisulfate

Sodium bisulfate is a salt which is used widely with potassium dichromate in bleach used for photographic purposes. It is a skin irritant and must be used with caution. If skin is exposed, wash with running water for 15 minutes. It is poison, so if ingested do not induce vomiting but seek immediate medical attention.

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Potassium Dichromate

K2Cr2O7

Potassium dichromate is a salt used to make bleach for photographic purposes. It is both toxic and an oxidizer (potential fire hazard). To dispose of excess solid potassium dichromate always wash the solid down the drain with large amounts of water. Never dispose of the solid in a wastebasket.

Spillage of a dichromate solution on the skin will cause a chemical burn, which will appear as an ulceration. In addition, all chromium compounds are potential carcinogens. Rubber gloves are recommended for handling this compound in solutions.

Common Salts
Inorganic Compounds
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Calcium Chloride

CaCl2

Calcium chloride is a salt that is marketed in pellet form for removing dampness from rooms. Remarkably hydroscopic, it is placed in perforated containers or on screens with a containers below them. Calcium chloride will collect enough water from the air to completely transform the pellets, leaving an empty basket and a volume of solution below it which is several times the volume of the original pellets.

Calcium chloride is also widely used as a deicer since it is effective in lowering the melting point when applied to ice. The melting point lowering occurs with any solute and is a colligative property, being proportional to the number of solute particles. Calcium chloride is a more effective deicer than sodium chloride since each molecule produces three ions in solution compared to two for NaCl. Calcium chloride is effective in melting ice down to -25°F, wheras sodium chloride loses its effectiveness at about 20°F and is not useful for this purpose below 15°F.

Calcium chloride is used for maintaining unpaved roads and for fortifying roadbases for new construction. It is sometimes used in concrete to allow it to be worked with less water, shortening drying time. It increases compressive strength and water resistance of concrete, but diminishes flexural and tensile strength. For that reason it is not permitted in pre-stressed concrete.

Common Salts
Inorganic Compounds
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