Sodium

Sodium is a chemical element with symbol Na with atomic number 11 that was discovered in 1807. It is a soft, oily alkaline metal, silvery in color, very abundant in nature, found in sea salt. It is highly reactive, burns with a yellow flame, oxidizes in the presence of oxygen, and reacts violently with water.

Sodium is present in large amounts in the ocean in ionic form. It is also a component of many minerals and an essential element for life.

Main features

Like other alkali metals, sodium is a soft, light, silver-colored metal that is not found free in nature. Sodium floats in water, decomposing it, giving off hydrogen and forming a hydroxide. Under the appropriate conditions it reacts spontaneously in water. It does not normally burn in air below 40°C.

Uses of Sodium

Sodium metal is used in organic synthesis as a reducing agent. It is also a component of sodium chloride necessary for life. Other uses are:

• In anti-friction alloys (gold).
• In the manufacture of deodorants (in combination with fatty acids).
• In the purification of molten metals.
• The Na K alloy is a material used for heat transfer as well as desicculating for organic solvents and as a reducer. At room temperature it is liquid. Sodium is also used as a refrigerant.
• Lead-leading is used in the manufacture of anti-detonant additives for gasoline.
• It is also used in the manufacture of photoelectric cells.
• Lighting by sodium steam lamps.
• Na oxides₂Or generated by oxygen-controlled combustion are used to exchange carbon dioxide for oxygen and thus regenerate the air in closed spaces (e.g. in submarines).
• Metallic sodium is also used in laboratories in the desicction of solvents.

Biological paper

The sodium cation (Na⁺) plays a fundamental role in cell metabolism, for example, in the transmission of nerve impulses (through the sodium-potassium pump mechanism i>). Maintains volume and osmolarity. It participates, in addition to the nerve impulse, in muscle contraction, acid-base balance and the absorption of nutrients by the membranes.

The plasma sodium concentration is 135−145 mmol/L under normal conditions. An increase in sodium in the blood is known as hypernatremia and its decrease hyponatremia.

History

Sodium (from the Italian soda, «soda»), known in various compounds, was isolated in 1807 by sir Humphry Davy by means of the electrolysis of caustic soda. In medieval Europe, a sodium compound called sodanum was used as a migraine remedy. The symbol for sodium (Na) comes from natron (or natrium, from the Greek nítron), a name formerly given to sodium carbonate.

Abundance

Sodium is relatively abundant in stars, detecting its presence through the D line of the solar spectrum, located approximately in yellow. The earth's crust contains about 2.6% sodium, making it the sixth most abundant element, and the most abundant of the alkali metals.

Currently it is obtained by electrolysis of molten sodium chloride (Downs process), a cheaper procedure than the one previously used, the electrolysis of sodium hydroxide (Castner-Kellner process). It is the cheapest alkali metal. Today it is mainly produced by the companies Métaux Spéciaux, in Pomblière St Marcel, France, and by Chemours, in Niagara Falls, USA.

The most abundant sodium compound is sodium chloride or common salt, although it is also present in various minerals such as halite and zeolites, etc.

Compounds

The most industrially important sodium compounds are:

• Common salt (NaCl), its use serves to flavor food and is released diluted in water when the human body releases it by the thermoregulation of the body.
• Sodium carbonate (Na₂CO₃).
• Sodium bicarbonate (NaHCO)₃).
• Sodium citrate
• Sodium hydroxide (NaOH), better known as sosa or caustic soda, is a very strong and corrosive base used in products intended for the cleaning of drains and the degreasing of furnaces, as well as the manufacture of soaps due to the saponification of fatty acids. When dissolved in water it produces a very ethermal reaction (-42.9 kJ/mol). Its corrosive power makes the caustic soda a lethal compound for living tissues and organic compounds, and can even attack the glass if the contact is permanent. In the presence of atmospheric carbon dioxide it produces sodium carbonate, so its solutions are unstable.
• Sodium nitrate (Nano)₃).
• Sodium Tiosulphate (Name)₂S₂O₃ · 5H₂O).
• Bórax (Na₂B₄O₇ · 10H₂O).
• Sodium iodide (NaI)
• Eritorbato de sodio (C₆H₇NaO₆), used in meats of all kinds and non-alcoholic beverages as a preservative. Human and lethal mutagen for some aquatic ecosystems.
• Sodium Tripoliphosphate (Na₅P₃O₁₀), fundamental component of soaps, detergents and different products to sweeten the hard waters. Also used in food.

Isotopes

Thirteen isotopes of sodium are known. The only stable one is Na-23. In addition, there are two radioactive isotopes (cosmogenic nuclides), Na-22 and Na-24, with half-lifes of 2,605 years and approximately 15 hours, respectively.

Sodium absorption and excretion

Sodium is easily absorbed in humans from the small intestine and from there it is carried to the kidneys, where it infiltrates and returns to the blood to maintain appropriate levels. The amount absorbed is proportional to the amount consumed. About 90-95% of normal sodium loss is through urine, with the rest in feces and sweat. It is considered that the normal amount of sodium excreted is equal to the amount ingested. Sodium secretion is maintained by a mechanism that involves the kidneys (glomerular filtration rate, renin-angiotensin system), sympathetic nervous system, catecholamine circulation, and blood pressure.

Functions

The sodium cation (Na⁺) plays a fundamental role in cellular metabolism, for example, in the transmission of nerve impulses (through the sodium-potassium pump mechanism). Maintains volume and osmolarity. It participates, in addition to the nerve impulse, in muscle contraction, acid-base balance and the absorption of nutrients by cells.

The plasma concentration of sodium is, under normal conditions, 135-145 mmol/L. An increase in sodium in the blood is known as hypernatremia and a decrease in it as hyponatremia. As the predominant cation (positive ion) of the extracellular fluid of animal and human fluids, sodium is used by the cell as a tool for regulating the size of that compartment as well as the volume of the plasma. These fluids, like blood plasma and extracellular fluids in other tissues bathe the cells and perform functions of transporting nutrients and waste substances in the body. Although the system for maintaining optimal salt and water balance in the body is complex, one of the main ways the body maintains this balance is through osmoreceptors located in the hypothalamus, and their subsequent action on the pituitary for the production of vasopressin. When sodium levels in the blood increase, thirst receptors (osmoreceptors) stimulate the sensation of thirst. When sodium levels in the blood are low, sodium excretion through the urine decreases.

The relative loss of water could cause sodium concentrations to become higher than normal, a condition known as hypernatremia, which results in extraordinary thirst. Conversely, an excess of body water due to greater intake will result in a lower concentration of sodium in the plasma, known as hyponatremia, a condition captured by the hypothalamus through its osmoreceptors, causing a decrease in the secretion of the hormone vasopressin from the pituitary gland. posterior or pituitary; this leads to a loss of water through the urine, which acts to restore plasma sodium concentrations to normal levels.

Severely dehydrated people, such as those rescued from the ocean or in desert survival situations, usually have high blood sodium concentrations. This must be carefully and slowly returned to normal, as too rapid a correction of hypernatremia can result in brain damage with cellular edema, as water moves rapidly into cells with a high osmolar content.

Because the osmoreceptor/hypothalamic system ordinarily works either to cause fluid intake or fluid elimination (urine) to restore sodium concentrations to normal, this system can be used in medical treatment to regulate total body fluid content, primarily to control body sodium content. Therefore, when a potentially diuretic drug is administered it can cause the kidneys to excrete sodium, the effect being accompanied by an excretion of body water. This happens because the kidney is unable to efficiently retain water while excreting large amounts of sodium. Additionally, after sodium excretion, the osmoreceptor system can capture low concentrations of sodium in the blood and then direct urinary water losses to correct hyponatremia.

In addition to this important function, sodium plays an important role in various physiological processes in the human body. Excitable animal cells, for example, allow sodium to enter their interior to cause depolarization of the cell membrane. An example of this is signal transduction in the human central nervous system, which depends on the movement of sodium across the cell membrane in all nerves. Some potent neurotoxins, such as batrachotoxins, increase the permeability of sodium in the cell membrane of nerve and muscle cells, causing massive and irreversible depolarization of the membranes, which has potentially fatal consequences for the organism. However, drugs with smaller effects on the movement of sodium in the nerves may have various pharmacological effects such as antidepressant effects, among others.

Hypernatremia

Hypernatremia is considered when the sodium concentration in plasma or blood is greater than 145 meq/L. The main causes are due to insufficient action of the hormone vasopressin or ADH (whether due to production deficit in the pituitary gland or lack of renal response), excessive water loss, and a positive salt balance. The clinical picture depends, as in most electrolyte disorders, on the magnitude and its form of establishment. The predominant symptom is thirst, which may be accompanied by polyuria (increased urine volume), diarrhea, and sweating. The presence of neurological disorders appear with values above 160 meq/L, which can be characterized by muscle irritability, altered level of consciousness, coma and even seizures.

Hyponatremia

Hyponatremia is considered when the plasma sodium concentration is less than 135 meq/L. The main causes include: large sodium losses (due to the use of diuretics, osmotic diuresis or loss of solutes through the urine that carry water and sodium, kidney diseases that increase urinary sodium loss.) increased intake or contribution of water to the body, which causes an increase in water at the extracellular level. Among the most common symptoms are nausea, vomiting, muscle cramps, visual disturbances, headache, lethargy. Seizures and coma. A decrease in sodium concentration below 125 meq/L is considered to be potentially fatal to the human body.

Sodium in the diet

The major source of sodium is sodium chloride (common salt), of which sodium makes up 40%. However, all foods naturally contain sodium, the concentration being more predominant in foods of animal than vegetable origin. Approximately 3 grams of sodium are contained in the foods that are consumed daily, without the addition of sodium chloride or common salt, this is important to consider in patients who have a restriction or decrease in daily salt intake (nephropathic patients, diabetics, hypertensive). The sodium requirement is approximately 500 mg/day. Most people consume more sodium than they physiologically need. For certain people with sodium-sensitive blood pressure, this extra amount can cause negative health effects.

Precautions

Photograph of a sodium explosion in contact with water.

In its metallic form, sodium is explosive in water and with many other elements. Metal must always be handled carefully and stored in an inert atmosphere, generally argon, avoiding contact with water and other substances with which sodium reacts, such as oxygen:

2Na + 2H₂Or------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 2NaOH + H₂(g)+ Energy

The explosion of sodium with water is due to the generation of hydrogen in it and with the consequent energy released by the exergonic reaction, explosions of the generated hydrogen can be produced. Therefore you must be very careful, work with caution and with the necessary elements to protect yourself from their chemical reactions.