Nahco3 название синоним

бикарбонат натрия

Натрия гидрокарбонат E500 (ii)

Натрий углекислый кислый

Гидрокарбонат натрия (лат. Natrii hydrocarbonas), другие названия: бикарбонат натрия, чайная сада, питьевая или пищевая сода, двууглекислый натрий — неорганическое соединение, натриевая кислая соль угольной кислоты с химической формулой NaHCO₃.

В обычном виде — мелкокристаллический порошок белого цвета.

Используется в промышленности, пищевой промышленности, в кулинарии, в медицине как нейтрализатор химических ожогов кожи и слизистых оболочек концентрированными кислотами и для снижения кислотности желудочного сока. Также применяется в буферных растворах.

Химические свойства

Гидрокарбонат натрия — кислая натриевая соль угольной кислоты. Проявляет все свойства соли сильного основания и слабой кислоты. В водных растворах имеет слабощелочную реакцию. В широком диапазоне концентраций в водном растворе pH раствора изменяется незначительно, на этом основано применение раствора вещества в качестве буферного раствора.

Реакция с кислотами

Гидрокарбонат натрия реагирует с кислотами с образованием соответствующей кислоте соли, например, хлорида натрия, сульфата натрия и угольной кислоты, которая в процессе реакции распадается на углекислый газ и воду, при этом углекислый газ выделяется из раствора в виде пузырьков:

 NaHCO₃ + HCl → NaCl + H₂CO₃

 H₂CO₃ → H₂O + CO₂↑

 2NaHCO₃ + H₂SO₄ → Na₂SO₄ + 2H₂O + 2CO₂↑

В быту обычно применяется реакция «гашения соды» уксусной кислотой, с образованием ацетата натрия или гашение лимонной кислотой с образование цитрата натрия, реакция с уксусной кислотой:

 NaHCO₃ + CH₃COOH → CH₃COONa + H₂O + CO₂↑

Термическое разложение

При температуре выше 60 °C гидрокарбонат натрия начинает распадаться на карбонат натрия, углекислый газ и воду (процесс разложения наиболее эффективен при 200 °C, при более высоких температурах карбонат натрия начинает распадаться на оксид натрия и углекислый газ):

 2NaHCO₃ →^60−200∘C Na₂CO₃ + H₂O + CO₂↑

При этом процессе выделения воды в виде водяного пара и углекислого газa масса исходного продукта уменьшается примерно на 37 %.

Получение

В промышленности гидрокарбонат натрия получают аммиачно-хлоридным способом. В концентрированный раствор хлорида натрия, насыщенный аммиаком, под давлением пропускают углекислый газ. В процессе синтеза происходят две реакции:

 NH₃ + CO₂ + H₂O → NH₄HCO₃

 NH₄HCO₃ + NaCl → NaHCO₃↓ + NH₄Cl

В холодной воде гидрокарбонат натрия мало растворим, и его отделяют от охлаждённого раствора фильтрованием, а из полученного после фильтрования раствора хлорида аммония снова получают аммиак, возвращаемый в производство вновь:

 2NH₄Cl + Ca(OH)₂ → 2NH₃↑ + CaCl₂ + 2H₂O

Применение

Двууглекислый натрий (бикарбонат) применяется в химической, пищевой, лёгкой, медицинской, фармацевтической промышленности, цветной металлургии, в быту. Зарегистрирован в качестве пищевой добавки E500 (ii), входит в состав пищевой добавки E500.

В химической промышленности

Применяется для производства красителей, пенопластов и других органических продуктов, фторорганических соединений, продуктов бытовой химии, наполнителей в огнетушителях, Реагент для отделения диоксида углерода, сероводорода из газовых смесей, например, отходящих газов топливосжигающих установок. В этом процессе углекислый газ поглощается раствором гидрокарбоната натрия при повышенном давлении и пониженной температуре, далее поглощённый углекислый газ выделяется из раствора при подогреве и снижении давления;

В лёгкой промышленности — в производстве резины для подошв обуви и в производстве искусственных кож, кожевенном производстве при дублении и нейтрализации кожи после кислого дубления, текстильной промышленности при отделке шёлковых и хлопчатобумажных тканей;

В пищевой промышленности — в хлебопечении, производстве кондитерских изделий, приготовлении газированных напитков.

В кулинарии

Основное применение пищевой соды в пищевой промышленности и в быту — кулинария, где применяется, преимущественно, в качестве основного или дополнительного разрыхлителя в составе кислого и пресного теста. При добавлении питьевой соды в кислое тесто происходит реакция с молочной кислотой, продуцированной при заквашивании дрожжевыми микроорганизмами, при этой реакции выделяется углекислый газ, вспучивающий тесто.

При добавлении в пресное тесто углекислый газ выделяется при выпечке из-за термического разложения.

При применении соды в чистом виде важно соблюсти правильную дозировку, так как она оставляет в продукте карбонат натрия, дающий определённый привкус. Порядок замешивания для теста: соду — в муку, кислые компоненты (уксус, кефир и пр.) — в жидкость.

В медицине

Традиционно раствор питьевой соды используется для дезинфекции зубов и дёсен при зубных болях и полости рта и горла, при сильном кашле, ангине, фарингите, а также как общепринятое средство от изжоги и болей в желудке.

Применяется при заболеваниях, сопровождающиеся выраженным ацидозом (при диабете, инфекциях и др), для борьбы с ацидозом при хирургических вмешательствах (назначается 3-5 г. внутрь).

Применяется в качестве антиаритмического средства.

Как антацидное средство (как и все другие щелочи) применяется при язвенной болезни желудка, и двенадцатиперстной кишки, при повышенной кислотности желудочного сока.

Имеются так же данные о применении препарата (в виде капельных и внутривенных вливаний) при гипертонической болезни, симптоматической почечной гипертонии, и хронической почечной недостаточности. Эффект связан с увеличением выделения ионов натрия и хлора и возрастанием осмотического диуреза.

В виде свечей применяется против укачивания при морской и воздушной болезнях

Применяется в качестве отхаркивающего средства, т.к. повышая щелочные резервы крови, сдвигает в щелочную сторону реакцию бронхиальной слизи, делая мокроту менее вязкой.

При ринитах, конъюнктивитах, стоматитах, ларингитах и т.п. применяют для полосканий, промываний, ингаляций 0,5 — 2% р-ры гидрокарбоната натрия.

Применяется внутривенно с целью быстрого устранения метаболического ацидоза во время реанимационных мероприятий, заболеваниях почек.

Нужно иметь ввиду, что в результате применения может возникнуть т.н. кислотный рикошет (при реакции содой с соляной кислотой происходит выделение CO₂, который оказывает раздражающее действие на стенку желудка, усиливая выделение гастрина).

В альтернативной медицине питьевая сода иногда заявляется как «лекарство» от рака, однако, никакой экспериментально подтверждённой эффективности применения такого «лечения» не существует.

Противопоказания к применению в медицинских целях

Индивидуальная гиперчувствительность; состояния, сопровождающиеся развитием алкалоза; гипокальциемия, при приеме внутрь усиливает алкалоз и повышает риск развития тетанических судорог, гипохлоремия — снижение концентрации в крови ионов Cl^—, в том числе вызванная рвотой, или снижением всасывания в желудочно-кишечном тракте, может привести к тяжёлому алкалозу.

Является источником натрия, тем самым увеличивая объём циркулирующей крови, усугубляя отёки и повышая артериальное давление. Применение при сниженной скорости клубочковой фильтрации может привести к метаболическому алкалозу.

Пожаротушение

Гидрокарбонат натрия вместе с карбонатом аммония используется в качестве наполнителя в огнетушителях с сухим наполнением и в стационарных системах сухого пожаротушения. Это применение обусловлено тем, что от воздействия высокой температуры в очаге горения вещество выделяет углекислый газ, атмосфера которого затрудняет доступ кислорода воздуха в очаг горения.

В быту

Применяется как безопасное для здоровья средство для чистки поверхностей столовой и кухонной посуды, поверхностей кухонных столов, иных поверхностей, соприкасающихся с пищей, путем протирки их с помощью влажной тряпки с сухим порошком питьевой соды.

В транспорте

Применяется для нейтрализации следов электролита — серной кислоты на поверхности пластмассовых корпусов свинцовых аккумуляторов насыщенным водным раствором питьевой соды.

Производство

В Российской Федерации двууглекислый натрий выпускается в соответствии с требованиями и техническими условиями, выпускается на предприятиях АО «Башкирская содовая компания» в г. Стерлитамак, Республика Башкортостан, а также на Крымском содовом заводе в г. Красноперекопск, Крымский полуостров.

Хранение

Гидрокарбонат натрия хранят в закрытых упаковках, в сухом месте вдали от источников огня. Гарантийный срок хранения натрия двууглекислого — 12 месяцев со дня изготовления. Срок годности не ограничен.

Безопасность

Вещество нетоксично, пожаро- и взрывобезопасно.

Имеет солоноватый, мыльный вкус. При попадании пыли вещества на слизистые оболочки глаз и носа вызывает лёгкое раздражение. При частой работе в атмосфере, загрязнённой пылью двууглекислого натрия, может возникнуть раздражение верхних дыхательных путей. Предельно допустимая концентрация пыли бикарбоната натрия в воздухе производственных помещений 5 мг/м³.

• ГОСТ 2156-76. Натрий двууглекислый. Технические условия (с Изменениями № 1, 2, 3, 4).
• ГОСТ 32802-2014. Добавки пищевые. Натрия карбонаты E500. Общие технические условия.

For the leavening agent of which baking soda is a common ingredient, see Baking powder.

Crystal structure
Na+ coordination HCO3− coordination
Names
IUPAC name sodium hydrogencarbonate
Other names Baking soda, bicarb (laboratory slang), bicarbonate of soda, nahcolite, natrium hydrogen carbonate, natron
Identifiers
CAS Number	144-55-8
3D model (JSmol)	Interactive image
Beilstein Reference	4153970
ChEBI	CHEBI:32139
ChEMBL	ChEMBL1353
ChemSpider	8609
DrugBank	DB01390
ECHA InfoCard	100.005.122
EC Number	205-633-8
E number	E500(ii) (acidity regulators, …)
IUPHAR/BPS	4507
KEGG	C12603
MeSH	Sodium+bicarbonate
PubChem CID	516892
RTECS number	VZ0950000
UNII	8MDF5V39QO
CompTox Dashboard (EPA)	DTXSID9021269
InChI InChI=1S/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1  Key: UIIMBOGNXHQVGW-UHFFFAOYSA-M  InChI=1/CH2O3.Na/c2-1(3)4;/h(H2,2,3,4);/q;+1/p-1 Key: UIIMBOGNXHQVGW-REWHXWOFAQ
SMILES [Na+].OC([O-])=O
Properties
Chemical formula	NaHCO 3
Molar mass	84.0066 g mol−1
Appearance	White crystals
Odor	Odorless
Density	2.20 g/cm3[1]
Melting point	(Decomposes to sodium carbonate starting at 50 °C[1][6])
Solubility in water	69 g/L (0 °C)[2][3] 96 g/L (20 °C)[2][3] 165 g/L (60 °C)[2][3]
Solubility	0.02 wt% acetone, 2.13 wt% methanol @22 °C.[4] insoluble in ethanol
log P	−0.82
Acidity (pKa)	6.34[5] 6.351 (carbonic acid)[5]
Refractive index (nD)	nα = 1.377 nβ = 1.501 nγ = 1.583
Structure
Crystal structure	Monoclinic
Thermochemistry
Heat capacity (C)	87.6 J/mol K[7]
Std molar entropy (S⦵298)	101.7 J/mol K[7]
Std enthalpy of formation (ΔfH⦵298)	−950.8 kJ/mol[7]
Gibbs free energy (ΔfG⦵)	−851.0 kJ/mol[7]
Pharmacology
ATC code	B05CB04 (WHO) B05XA02 (WHO), QG04BQ01 (WHO)
Routes of administration	Intravenous, oral
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Causes serious eye irritation
NFPA 704 (fire diamond)	2 0 1
Flash point	Incombustible
Lethal dose or concentration (LD, LC):
LD50 (median dose)	4220 mg/kg (rat, oral)[8]
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Sodium carbonate
Other cations	Ammonium bicarbonate Potassium bicarbonate
Related compounds	Sodium bisulfate Sodium hydrogen phosphate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).  verify (what is  ?) Infobox references

Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate^[9]), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO₃. It is a salt composed of a sodium cation (Na⁺) and a bicarbonate anion (HCO₃⁻). Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite. It is a component of the mineral natron and is found dissolved in many mineral springs.^[10]

Nomenclature[edit]

Because it has long been known and widely used, the salt has many different names such as baking soda, bread soda, cooking soda, and bicarbonate of soda and can often be found near baking powder in stores. The term baking soda is more common in the United States, while bicarbonate of soda is more common in Australia, United Kingdom and Ireland.^[11] Abbreviated colloquial forms such as sodium bicarb, bicarb soda, bicarbonate, and bicarb are common.^[12]

The word saleratus, from Latin sal æratus (meaning «aerated salt»), was widely used in the 19th century for both sodium bicarbonate and potassium bicarbonate.^[13]

Its E number food additive code is E500.^[14]

The prefix bi in bicarbonate comes from an outdated naming system predating molecular knowledge. It is based on the observation that there is twice as much carbonate (CO3) per sodium in sodium bicarbonate (NaHCO3) as there is in sodium carbonate (Na2CO3).^[15] The modern chemical formulas of these compounds now express their precise chemical compositions which were unknown when the name bi-carbonate of potash was coined (see also: bicarbonate).

Uses[edit]

Cooking[edit]

Leavening[edit]

In cooking, baking soda is primarily used in baking as a leavening agent. When it reacts with acid, carbon dioxide is released, which causes expansion of the batter and forms the characteristic texture and grain in cakes, quick breads, soda bread, and other baked and fried foods. The acid–base reaction can be generically represented as follows:^[16]

NaHCO₃ + H⁺ → Na⁺ + CO₂ + H₂O

Acidic materials that induce this reaction include hydrogen phosphates, cream of tartar, lemon juice, yogurt, buttermilk, cocoa, and vinegar. Baking soda may be used together with sourdough, which is acidic, making a lighter product with a less acidic taste.^[17]

Heat can also by itself cause sodium bicarbonate to act as a raising agent in baking because of thermal decomposition, releasing carbon dioxide at temperatures above 80 °C (180 °F), as follows:^[18]

2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂

When used this way on its own, without the presence of an acidic component (whether in the batter or by the use of a baking powder containing acid), only half the available CO₂ is released (one CO₂ molecule is formed for every two equivalents of NaHCO₃). Additionally, in the absence of acid, thermal decomposition of sodium bicarbonate also produces sodium carbonate, which is strongly alkaline and gives the baked product a bitter, «soapy» taste and a yellow color. Since the reaction occurs slowly at room temperature, mixtures (cake batter, etc.) can be allowed to stand without rising until they are heated in the oven.^{[citation needed]}

Baking powder[edit]

Baking powder, also sold for cooking, contains around 30% of bicarbonate, and various acidic ingredients which are activated by the addition of water, without the need for additional acids in the cooking medium.^[19][20][21] Many forms of baking powder contain sodium bicarbonate combined with calcium acid phosphate, sodium aluminium phosphate, or cream of tartar.^[22] Baking soda is alkaline; the acid used in baking powder avoids a metallic taste when the chemical change during baking creates sodium carbonate.^[23]

Pyrotechnics[edit]

Sodium bicarbonate is one of the main components of the common «black snake» firework. The effect is caused by the thermal decomposition, which produces carbon dioxide gas to produce a long snake-like ash as a combustion product of the other main component, sucrose.^[24] Sodium bicarbonate is also used to delay combustion reactions by releasing CO₂ and H₂O when heated, both of which are flame retardants.

Mild disinfectant[edit]

It has weak disinfectant properties,^[25][26] and it may be an effective fungicide against some organisms.^[27] Because baking soda will absorb musty smells, it has become a reliable method for used book sellers when making books less malodorous.^[28]

Fire extinguisher[edit]

Sodium bicarbonate can be used to extinguish small grease or electrical fires by being thrown over the fire, as heating of sodium bicarbonate releases carbon dioxide.^[29] However, it should not be applied to fires in deep fryers; the sudden release of gas may cause the grease to splatter.^[29] Sodium bicarbonate is used in BC dry chemical fire extinguishers as an alternative to the more corrosive monoammonium phosphate in ABC extinguishers. The alkaline nature of sodium bicarbonate makes it the only dry chemical agent, besides Purple-K, that was used in large-scale fire suppression systems installed in commercial kitchens. Because it can act as an alkali, the agent has a mild saponification effect on hot grease, which forms a smothering, soapy foam.^{[citation needed]}

Neutralization of acids[edit]

Sodium bicarbonate reacts spontaneously with acids, releasing CO₂ gas as a reaction product. It is commonly used to neutralize unwanted acid solutions or acid spills in chemical laboratories.^[30] It is not appropriate to use sodium bicarbonate to neutralize base^[31] even though it is amphoteric, reacting with both acids and bases.^{[citation needed]}

Sports Supplement[edit]

Sodium bicarbonate is taken as a sports supplement to improve muscular endurance.^[32]

Agriculture[edit]

Sodium bicarbonate when applied on leaves, can prevent the growth of fungi; however, it does not kill the fungus. Excessive amount of sodium bicarbonate can cause discolouration of fruits (two percent solution) and chlorosis (one percent solution).^[33]

Medical uses and health[edit]

Sodium bicarbonate mixed with water can be used as an antacid to treat acid indigestion and heartburn.^[34] Its reaction with stomach acid produces salt, water, and carbon dioxide:

NaHCO₃ + HCl → NaCl + H₂O + CO₂(g)

A mixture of sodium bicarbonate and polyethylene glycol such as PegLyte,^[35] dissolved in water and taken orally, is an effective gastrointestinal lavage preparation and laxative prior to gastrointestinal surgery, gastroscopy, etc.^{[citation needed]}

Intravenous sodium bicarbonate in an aqueous solution is sometimes used for cases of acidosis, or when insufficient sodium or bicarbonate ions are in the blood.^[36] In cases of respiratory acidosis, the infused bicarbonate ion drives the carbonic acid/bicarbonate buffer of plasma to the left, and thus raises the pH. For this reason, sodium bicarbonate is used in medically supervised cardiopulmonary resuscitation. Infusion of bicarbonate is indicated only when the blood pH is markedly low (< 7.1–7.0).^[37]

HCO₃⁻ is used for treatment of hyperkalemia, as it will drive K⁺ back into cells during periods of acidosis.^[38] Since sodium bicarbonate can cause alkalosis, it is sometimes used to treat aspirin overdoses. Aspirin requires an acidic environment for proper absorption, and a basic environment will diminish aspirin absorption in cases of overdose.^[39] Sodium bicarbonate has also been used in the treatment of tricyclic antidepressant overdose.^[40] It can also be applied topically as a paste, with three parts baking soda to one part water, to relieve some kinds of insect bites and stings (as well as accompanying swelling).^[41]

Some alternative practitioners, such as Tullio Simoncini, have promoted baking soda as a cancer cure, which the American Cancer Society has warned against due to both its unproven effectiveness and potential danger in use.^[42] Edzard Ernst has called the promotion of sodium bicarbonate as a cancer cure «one of the more sickening alternative cancer scams I have seen for a long time».^[43]

Sodium bicarbonate can be added to local anesthetics, to speed up the onset of their effects and make their injection less painful.^[44] It is also a component of Moffett’s solution, used in nasal surgery.^{[citation needed]}

It has been proposed that acidic diets weaken bones.^[45] One systematic meta-analysis of the research shows no such effect.^[46] Another also finds that there is no evidence that alkaline diets improve bone health, but suggests that there «may be some value» to alkaline diets for other reasons.^[47]

Antacid (such as baking soda) solutions have been prepared and used by protesters to alleviate the effects of exposure to tear gas during protests.^{[failed verification][48]}

Similarly to its use in baking, sodium bicarbonate is used together with a mild acid such as tartaric acid as the excipient in effervescent tablets: when such a tablet is dropped in a glass of water, the carbonate leaves the reaction medium as carbon dioxide gas (HCO₃⁻ + H⁺ → H₂O + CO₂↑ or, more precisely, HCO₃⁻ + H₃O⁺ → 2 H₂O + CO₂↑). This makes the tablet disintegrate, leaving the medication suspended and/or dissolved in the water together with the resulting salt (in this example, sodium tartrate).^[49]

Personal hygiene[edit]

Sodium bicarbonate is also used as an ingredient in some mouthwashes. It has anticaries and abrasive properties.^[50] It works as a mechanical cleanser on the teeth and gums, neutralizes the production of acid in the mouth, and also acts as an antiseptic to help prevent infections.^[51][52] Sodium bicarbonate in combination with other ingredients can be used to make a dry or wet deodorant.^[53][54] Sodium bicarbonate may be used as a buffering agent, combined with table salt, when creating a solution for nasal irrigation.^[55]

It is used in eye hygiene to treat blepharitis. This is done by addition of a teaspoon of sodium bicarbonate to cool water that was recently boiled, followed by gentle scrubbing of the eyelash base with a cotton swab dipped in the solution.^[56][57]

Veterinary uses[edit]

Sodium bicarbonate is used as a cattle feed supplement, in particular as a buffering agent for the rumen.^[58]

Cleaning agent[edit]

Sodium bicarbonate is used in a process for removing paint and corrosion called sodablasting. As a blasting medium, sodium bicarbonate is used to remove surface contamination from softer and less resilient substrates such as aluminium, copper or timber which could be damaged by silica sand abrasive media.^[59]

A manufacturer recommends a paste made from baking soda with minimal water as a gentle scouring powder.^[29] Such a paste can be useful in removing surface rust, as the rust forms a water-soluble compound when in a concentrated alkaline solution.^[60] Cold water should be used, as hot-water solutions can corrode steel.^[61] Sodium bicarbonate attacks the thin protective oxide layer that forms on aluminium, making it unsuitable for cleaning this metal.^[62] A solution in warm water will remove the tarnish from silver when the silver is in contact with a piece of aluminium foil.^[62][63] Baking soda is commonly added to washing machines as a replacement for water softener and to remove odors from clothes. It is also almost as effective in removing heavy tea and coffee stains from cups as sodium hydroxide, when diluted with warm water.

During the Manhattan Project to develop the nuclear bomb in the early 1940s, the chemical toxicity of uranium was an issue. Uranium oxides were found to stick very well to cotton cloth, and did not wash out with soap or laundry detergent. However, the uranium would wash out with a 2% solution of sodium bicarbonate. Clothing can become contaminated with toxic dust of depleted uranium (DU), which is very dense, hence used for counterweights in a civilian context, and in armour-piercing projectiles. DU is not removed by normal laundering; washing with about 6 ounces (170 g) of baking soda in 2 gallons (7.5 L) of water will help to wash it out.^[64]

Odor control[edit]

It is often claimed that baking soda is an effective odor remover,^{[65][better source needed]} and it is often recommended that an open box be kept in the refrigerator to absorb odor.^[66] This idea was promoted by the leading U.S. brand of baking soda, Arm & Hammer, in an advertising campaign starting in 1972.^[67] Though this campaign is considered a classic of marketing, leading within a year to more than half of American refrigerators containing a box of baking soda,^[68][69] there is little evidence that it is in fact effective in this application.^[70][71]

Hydrogen gas production[edit]

Sodium bicarbonate can be used as a catalyst in gas production. Its performance for this application is «good», however not usually used.^{[citation needed]} Hydrogen gas is produced via electrolysis of water, process in which electric current is applied through a volume of water, which causes the hydrogen atoms to separate from the oxygen atoms. This demonstration is usually done in high school chemistry classes to show electrolysis.

Chemistry[edit]

Sodium bicarbonate is an amphoteric compound. Aqueous solutions are mildly alkaline due to the formation of carbonic acid and hydroxide ion:

HCO⁻
₃ + H₂O → H
₂CO
₃ + OH⁻

Sodium bicarbonate can often be used as a safer alternative to sodium hydroxide, and as such can be used as a wash to remove any acidic impurities from a «crude» liquid, producing a purer sample. Reaction of sodium bicarbonate and an acid produces a salt and carbonic acid, which readily decomposes to carbon dioxide and water:

NaHCO₃ + HCl → NaCl + H₂O+CO₂

H₂CO₃ → H₂O + CO₂(g)

Sodium bicarbonate reacts with acetic acid (found in vinegar), producing sodium acetate, water, and carbon dioxide:

NaHCO₃ + CH₃COOH → CH₃COONa + H₂O + CO₂(g)

Sodium bicarbonate reacts with bases such as sodium hydroxide to form carbonates:

NaHCO₃ + NaOH → Na₂CO₃ + H₂O

Thermal decomposition[edit]

At temperatures from 80–100 °C (176–212 °F), sodium bicarbonate gradually decomposes into sodium carbonate, water, and carbon dioxide. The conversion is faster at 200 °C (392 °F):^[72]

2 NaHCO₃ → Na₂CO₃ + H₂O + CO₂

Most bicarbonates undergo this dehydration reaction. Further heating converts the carbonate into the oxide (above 850 °C/1,560 °F):^[72]

Na₂CO₃ → Na₂O + CO₂

These conversions are relevant to the use of NaHCO₃ as a fire-suppression agent («BC powder») in some dry-powder fire extinguishers.^{[citation needed]}

Stability and shelf life[edit]

If kept cool (room temperature) and dry (an airtight container is recommended to keep out moist air), sodium bicarbonate can be kept without a significant amount of decomposition for at least two or three years.^{[73][74][75][76]}

History[edit]

The word natron has been in use in many languages throughout modern times (in the forms of anatron, natrum and natron) and originated (like Spanish, French and English natron as well as ‘sodium’) via Arabic naṭrūn (or anatrūn; cf. the Lower Egyptian “Natrontal” Wadi El Natrun, where a mixture of sodium carbonate and sodium hydrogen carbonate for the dehydration of mummies was used ^[77]) from Greek nítron (νίτρον) (Herodotus; Attic lítron (λίτρον)), which can be traced back to ancient Egyptian ntr. The Greek nítron (soda, saltpeter) was also used in Latin (sal) nitrum and in German Salniter (the source of Nitrogen, Nitrat etc.).^[78][79]

In 1791, French chemist Nicolas Leblanc produced sodium carbonate, also known as soda ash. The pharmacist Valentin Rose the Younger is credited with the discovery of sodium bicarbonate in 1801 in Berlin. In 1846, two American bakers, John Dwight and Austin Church, established the first factory in the United States to produce baking soda from sodium carbonate and carbon dioxide.^[80]

Saleratus, potassium or sodium bicarbonate, is mentioned in the novel Captains Courageous by Rudyard Kipling as being used extensively in the 1800s in commercial fishing to prevent freshly caught fish from spoiling.^[81]

In 1919, US Senator Lee Overman declared that bicarbonate of soda could cure the Spanish flu. In the midst of the debate on 26 January 1919, he interrupted the discussion to announce the discovery of a cure. «I want to say, for the benefit of those who are making this investigation,» he reported, «that I was told by a judge of a superior court in the mountain country of North Carolina they have discovered a remedy for this disease.» The purported cure implied a critique of modern science and an appreciation for the simple wisdom of simple people. «They say that common baking soda will cure the disease,» he continued, «that they have cured it with it, that they have no deaths up there at all; they use common baking soda, which cures the disease.»^[82]

Production[edit]

Sodium bicarbonate is produced industrially from sodium carbonate:^[83]

Na₂CO₃ + CO₂ + H₂O → 2 NaHCO₃

It is produced on the scale of about 100,000 tonnes/year (as of 2001)^{[dubious – discuss][84]} with a worldwide production capacity of 2.4 million tonnes per year (as of 2002).^[85] Commercial quantities of baking soda are also produced by a similar method: soda ash, mined in the form of the ore trona, is dissolved in water and treated with carbon dioxide. Sodium bicarbonate precipitates as a solid from this solution.^{[citation needed]}

Regarding the Solvay process, sodium bicarbonate is an intermediate in the reaction of sodium chloride, ammonia, and carbon dioxide. The product however shows low purity (75pc).^{[citation needed]}

NaCl + CO₂ + NH₃ + H₂O → NaHCO₃ + NH₄Cl

Although of no practical value, NaHCO₃ may be obtained by the reaction of carbon dioxide with an aqueous solution of sodium hydroxide:^{[citation needed]}

CO₂ + NaOH → NaHCO₃

Mining[edit]

Naturally occurring deposits of nahcolite (NaHCO₃) are found in the Eocene-age (55.8–33.9 Mya) Green River Formation, Piceance Basin in Colorado. Nahcolite was deposited as beds during periods of high evaporation in the basin. It is commercially mined using common underground mining techniques such as bore, drum, and longwall mining in a fashion very similar to coal mining.^{[citation needed]}

It is also produced by solution mining, pumping heated water through nahcolite beds and crystalizing the dissolved nahcolite through a cooling crystallization process.

In popular culture[edit]

Sodium bicarbonate, as «bicarbonate of soda», was a frequent source of punch lines for Groucho Marx in Marx Brothers movies. In Duck Soup, Marx plays the leader of a nation at war. In one scene, he receives a message from the battlefield that his general is reporting a gas attack, and Groucho tells his aide: «Tell him to take a teaspoonful of bicarbonate of soda and a half a glass of water.»^[86] In A Night at the Opera, Groucho’s character addresses the opening night crowd at an opera by saying of the lead tenor: «Signor Lassparri comes from a very famous family. His mother was a well-known bass singer. His father was the first man to stuff spaghetti with bicarbonate of soda, thus causing and curing indigestion at the same time.»^[87]

In the Joseph L. Mankewicz classic All About Eve, the Max Fabian character (Gregory Ratoff) has an extended scene with Margo Channing (Bette Davis) in which, suffering from heartburn, he requests and then drinks bicarbonate of soda, eliciting a prominent burp. Channing promises to always keep a box of bicarb with Max’s name on it.

See also[edit]

References[edit]

Bibliography[edit]

External links[edit]

• International Chemical Safety Card 1044