Cooking In cooking, baking soda is primarily used in
baking as a
leavening agent. When it reacts with acid or is heated, 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. When an acid is used, the
acid–base reaction can be generically represented as follows: :NaHCO3 + H+ → Na+ + CO2 + H2O Acidic materials that induce this reaction include
hydrogen phosphates,
cream of tartar,
citric acid,
lactic acid and
vinegar. 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 , as follows:3 → Na2CO3·2 NaHCO3 + CO2 + H2O so that only one quarter of the available CO2 is released. --> : 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.
Baking powder Baking powder, also sold for cooking, contains around 30% of bicarbonate, and various acidic ingredients that are activated by the addition of water, without the need for additional acids in the cooking medium. Many forms of baking powder contain sodium bicarbonate combined with
calcium acid phosphate,
sodium aluminium phosphate, or
cream of tartar. Baking soda is alkaline; the acid used in baking powder avoids a metallic taste when the chemical change during baking creates sodium carbonate.
Food additive Sodium bicarbonate is often used in conjunction with other
bottled water food additives to add taste. Its
European Union E number is E500.
Pyrotechnics 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. Sodium bicarbonate delays combustion through the release of flame retardants carbon dioxide and water when heated.
Mild disinfectant Sodium bicarbonate has weak
disinfectant properties and it may be an effective
fungicide against some organisms.
Fire extinguisher 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. However, it should not be applied to fires in
deep fryers; the sudden release of gas may cause the grease to splatter. Sodium bicarbonate has several fire-extinguishing mechanisms that act simultaneously. It decomposes into water and carbon dioxide when heated, an
endothermic reaction that deprives the fire of heat. In addition, it forms intermediates that can scavenge the
free radicals which are responsible for the
propagation of fire. With
grease fires specifically, it also has a mild
saponification effect, producing a soapy foam that can help smother the fire. It is not appropriate to use sodium bicarbonate to neutralize base even though it is
amphoteric, reacting with both acids and bases.
Sports supplement Sodium bicarbonate is taken as a sports supplement to improve muscular endurance. Studies conducted mostly in males have shown that sodium bicarbonate is most effective in enhancing performance in short-term, high-intensity activities, and it has been observed to take off an average of 5 minutes and 35 seconds off most elite athletes 2 mile times.
Agriculture Sodium bicarbonate can prevent the growth of fungi when applied on leaves, although it will not kill the fungus. Excessive amounts of sodium bicarbonate can cause discolouration of fruits (two percent solution) and
chlorosis (one percent solution). Sodium bicarbonate is also commonly used as a free choice dietary supplement in sheep to help prevent bloat.
Medical uses and health Sodium bicarbonate mixed with water can be used as an
antacid to treat
acid indigestion and
heartburn. 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 dissolved in water and taken orally, is an effective
gastrointestinal lavage preparation and
laxative prior to gastrointestinal surgery,
gastroscopy, etc.
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. 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). HCO3− is used for treatment of
hyperkalemia, as it will drive K+ back into cells during periods of acidosis. 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. Sodium bicarbonate has also been used in the treatment of
tricyclic antidepressant overdose. 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). 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.
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". Sodium bicarbonate can be added to
local anaesthetics, to speed up the onset of their effects and make their injection less painful. It is also a component of
Moffett's solution, used in
nasal surgery. It has been proposed that acidic diets weaken bones. One systematic meta-analysis of the research shows no such effect. 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.
Antacid (such as baking soda) solutions have been prepared and used by protesters to alleviate the effects of exposure to
tear gas during protests. 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).
Personal hygiene Sodium bicarbonate is also used as an ingredient in some mouthwashes. It has anticaries and abrasive properties. 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. Sodium bicarbonate in combination with other ingredients can be used to make a dry or wet
deodorant. Sodium bicarbonate may be used as a
buffering agent, combined with table salt, when creating a solution for
nasal irrigation. It is used in eye hygiene to treat
blepharitis. This is done by adding 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.
Veterinary uses Sodium bicarbonate is used as a cattle feed supplement, in particular as a
buffering agent for the
rumen.
Cleaning agent Sodium bicarbonate is used in a process to remove 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 that could be damaged by silica sand abrasive media. A manufacturer recommends a paste made from baking soda with minimal water as a gentle scouring powder. Cold water should be used since hot-water solutions can corrode steel. Sodium bicarbonate attacks the thin protective oxide layer that forms on aluminium, making it unsuitable for cleaning this metal. A solution of baking soda in warm water will remove the
tarnish from silver when the silver is in contact with a piece of
aluminium foil. 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.
Odor control It is often claimed that baking soda is an effective odor remover and recommended that an open box be kept in the refrigerator to absorb odor. This idea was promoted by the leading U.S. brand of baking soda,
Arm & Hammer, in an advertising campaign starting in 1972. 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, there is little evidence that it is effective in this application. However, baking soda may be effective in absorbing musty smells in books.
Education An educational science experiment known as the "Baking Soda and Vinegar Volcano" uses the acid-base reaction with
vinegar acid to mimic a volcanic eruption. The rapid production of CO2 causes the liquid to foam up and overflow its container. Other ingredients such as dish soap and food coloring can be added to enhance the visual effect. If this reaction is performed inside of a closed vessel (such as a bottle) with no way for gas to escape, it can cause an
explosion if the pressure is high enough. ==Chemistry==