Salt

How much salt to add to the usual boiled potatoes. As a rule, in all cookbooks they write: “To taste!”. But what does it mean to your taste. The taste is different for everyone. I will try to figure out if there is a correct dose of salt in food and what it is.
First, let's look at what salt is. Salt, also has the name of salt, food salt is sodium chloride (NaCl). It is a crystal of transparent color, in the mass they give white color. Salt of marine origin in its composition has impurities of other mineral salts. Therefore, this salt has shades, usually gray or brown.

[Halit crystals, also Salt crystals](By The original uploader was W.J.Pilsak at German Wikipedia. - Transferred from de.wikipedia to Commons., CC BY-SA 3.0, Link)
If you carefully read the labels on your products, then you will see that the salt content is different everywhere. For example, in chocolate it is much less than 1%, and in potato chips about 9%, in canned vegetables about 1%.
From a chemical point of view, table salt is sodium chloride. Ion-bonded atoms of chlorine and sodium. Individually, these substances are not edible. Sodium is an alkali metal that is very active. It is light, soft, oxidizes rapidly in air, reacts violently with water, with an explosion. Chlorine in its purest form is yellowish-green gas, which is poison. Chlorine is heavier than air, with a pungent smell and a sweetish “metallic” taste. Chlorine does not burn in air, the mixture with hydrogen explodes in the light. When chlorinated water kills bacteria. Chlorine was also the first poisoned agent used in the war.

[Sodium metal from the Dennis s.k collection. Selfmade photo taken 12/12-07](By The original uploader was Dnn87 at English Wikipedia. - Transferred from en.wikipedia to Commons., CC BY-SA 3.0, Link)

[Chlorine gas in an ampoule](By W. Oelen - http://woelen.homescience.net/science/index.html, CC BY-SA 3.0, Link)
Sodium and chlorine react: 2Na + Cl₂ = 2NaCl + Q

As you can see as a result of the interaction of explosives, and chlorine is also poison, it turns out to be quite so peaceful a substance used in food, called salt. In a flask filled with chlorine, put small pieces of sodium. There are flashes, fire, and then thick white smoke! Reminds pyrotechnic spectacle! We get salt, which is used by man in cooking, as a flavoring agent; in medicine - for therapeutic solutions that relieve swelling; against ice, sprinkling the road; to soften the water; as well as in the chemical industry. The well-known saline solution, which saved the lives of many people, is a 0.9% aqueous solution of sodium chloride. Here is such a useful thing salt.

[Iv1-07 014](CC BY-SA 3.0, Link)
It is not known from where the habit of adding salt to food has gone. But people living on the shores of salt ponds, seas and oceans, noticed that if you add salt to food, then the food became tastier. In nature, salt is most often found in the form of the halite mineral. Common mineral saliferous strata. It is formed during sedimentation in closed reservoirs, and also as a product of sgon on the walls of craters of volcanoes.
So how much need to add salt in food. In the human body is contained. An adult’s body contains about 4,000 mmol of sodium, which is equivalent to 256 g of sodium chloride, which is about 0.4% salt by weight. If this value changes dramatically, then a person will have strong health problems. Sodium ions play an important role in maintaining the constancy of the volume of fluid in the body. Delay or loss of sodium causes proportional delay or loss of water. In addition, sodium ions are involved in the transport of amino acids, sugars and potassium into cells. Sodium and chlorine ions are involved in the formation of hydrochloric acid in the stomach. Therefore, you can not drink distilled water or too salty. So, as this can lead to an imbalance of the salt balance in the body.
It is necessary to add salt to food as much as it is contained as a percentage in our body, but not more than in saline solution - it is from 0.4% to 0.9%. If you add more, the taste will deteriorate ... The person does not have salt receptors in the language. Several receptors that respond to sour and greasy taste, as well as to sodium ions, are responsible for the salty taste. Therefore, most products containing sodium ions will have a salty taste. The taste of bitter foods will weaken in the presence of salt. Therefore, we often drink beer with salty snacks. If you add salt to coffee, you can also improve the taste, who do not like too bitter. Recently, salt has been added to the sweet caramel, which makes the taste of caramel more vivid. A large concentration of salt, makes the products bitter and not tasty.