Is Naoh Acidic Or Basic

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Sodium hydroxide

General
Systematic name	Sodium hydroxide
Other names	Lye, Caustic Soda
Molecular formula	NaOH
Molar mass	39.9971 g/mol
Appearance	White flakes
CAS number	[1310-73-2]
Backdrop
Density and phase	2.1 1000/cm³, solid
Solubility in h2o	111 g/100 ml (xx°C)
Melting point	318°C (591 K)
Boiling bespeak	1390°C (1663 Grand)
Basicity (pK _b)	0.2
Hazards
MSDS	External MSDS
EU classification	Corrosive (C)
R-phrases	R35
South-phrases	S1/2, S26, S37/39, S45
NFPA 704	0 3 1
Wink betoken	Not-flammable.
Supplementary data folio
Construction and backdrop	northward, ε_r, etc.
Thermodynamic data	Stage behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	Sodium chloride Sodium sulfate.
Other cations	Potassium hydroxide Calcium hydroxide
Related bases	Ammonia, lime.
Related compounds	Chlorine
Except where noted otherwise, data are given for materials in their standard land (at 25 °C, 100 kPa) Infobox disclaimer and references

Sodium hydroxide (Na OH), also known as lye or caustic soda, is a caustic metallic base. An alkali, caustic soda is widely used in many industries, mostly as a strong chemical base of operations in the manufacture of pulp and newspaper, textiles, drinking h2o, and detergents. Worldwide product in 1998 was around 45 1000000 tonnes. Sodium hydroxide is also the most common base used in chemical laboratories, being able to test for quite a number of cations (this is called Qualitative Inorganic Analysis), every bit well as to provide alkaline mediums for some reactions that need it, such equally the Biuret test.

General properties

Pure sodium hydroxide is a white solid, bachelor in pellets, flakes, granules, and too fifty% saturated solution. It is deliquescent and besides readily absorbs carbon dioxide from the air, so it should be stored in an airtight container. It is very soluble in water with liberation of heat. It also dissolves in ethanol and methanol, though it exhibits lower solubility in these solvents than does potassium hydroxide. Information technology is insoluble in ether and other non-polar solvents. A sodium hydroxide solution volition leave a yellowish stain on fabric and paper.

Chemic properties

Sodium hydroxide is completely ionic, containing sodium ions and hydroxide ions. The hydroxide ion makes sodium hydroxide a strong base which reacts with acids to form water and the corresponding salts, e.thou., with hydrochloric acrid, sodium chloride is formed:

NaOH( aq) + HCl(aq) → NaCl(aq) + H_iiO( 50)

In general such neutralization reactions are represented by 1 elementary net ionic equation:

OH⁻(aq) + H⁺(aq) → H_twoO

This type of reaction releases heat when a strong acrid is used. Such acid-base reactions can also be used for titrations, and indeed this is a common way for measuring the concentration of acids. Related to this is the reaction of sodium hydroxide with acidic oxides. The reaction of carbon dioxide has already been mentioned, only other acidic oxides such as sulfur dioxide (SO_ii) likewise react completely. Such reactions are oft used to "scrub" harmful acidic gases (like SO₂ and H_iiS) and prevent their release into the atmosphere.

2NaOH + CO_ii → Na₂CO₃ + H₂O

Sodium hydroxide slowly reacts with glass to form sodium silicate, so glass joints and stopcocks exposed to NaOH have a trend to "freeze". Flasks and drinking glass-lined chemical reactors are damaged past long exposure to hot sodium hydroxide, and the drinking glass becomes frosted. Sodium hydroxide does non attack iron or copper, simply many other metals such every bit aluminium, zinc and titanium are attacked rapidly. In 1986 an aluminium road tanker in the UK was mistakenly used to ship 25% sodium hydroxide solution, causing pressurisation of the contents and harm to the tanker. For this same reason aluminium pans should never be cleaned with lye.

2Al( s) + 6NaOH(aq) → 3H₂(thousand) + 2Na_iiiAlO₃(aq)

Many non-metals also react with sodium hydroxide, giving salts. For instance phosphorus forms sodium hypophosphite, while silicon gives sodium silicate.

Unlike NaOH, the hydroxides of most metals are insoluble, and therefore sodium hydroxide can be used to precipitate metal hydroxides. One such hydroxide is aluminium hydroxide, used as a gelatinous floc to filter out particulate matter in water treatment. Aluminium hydroxide is prepared at the treatment plant from aluminium sulfate past reaction with NaOH:

6NaOH(aq) + Al₂(And then_iv)₃(aq) → 2 Al(OH)₃(s) + 3Na₂SO₄(aq)

Sodium hydroxide reacts readily with carboxylic acids to course their salts, and information technology is even a strong plenty base to form salts with phenols. NaOH tin can also exist used for the base-driven hydrolysis of esters (as is saponification), amides and alkyl halides. Notwithstanding, the limited solubility of NaOH in organic solvents means that the more soluble KOH is often preferred.

Basic hydrolysis of an ester

Bones hydrolysis of an ester

Manufacture

In 1998, total globe production was around 45 million tonnes. Of this, both North America and Asia contributed around 14 1000000 tonnes, and Europe produced around 10 meg tonnes.

Methods of product

Sodium hydroxide is produced (forth with chlorine and hydrogen) via the chloralkali process. This involves the electrolysis of an aqueous solution of sodium chloride. The sodium hydroxide builds up at the cathode, where water is reduced to hydrogen gas and hydroxide ion:

2Na⁺ + 2H_iiO + 2e⁻ → H₂ + 2NaOH

To produce NaOH it is necessary to prevent reaction of the NaOH with the chlorine. This is typically washed in one of three ways, of which the membrane jail cell procedure is economically the near viable.

Mercury cell process – sodium metal forms as an constructing at a mercury cathode; this sodium is and so reacted with h2o to produce NaOH. At that place have been concerns about mercury releases, although modernistic plants claim to be safe in this regard.
Diaphragm cell process – uses a steel cathode, and reaction of NaOH with Cl₂ is prevented using a porous diaphragm. In the diaphragm cell process the anode area is separated from the cathode area by a permeable diaphragm. The brine is introduced into the anode compartment and flows through the diaphragm into the cathode compartment. A diluted caustic brine leaves the prison cell. The caustic soda must ordinarily be concentrated to 50% and the table salt removed. This is washed using an evaporative process with about three tonnes of steam per tonne of caustic soda. The salt separated from the caustic brine can exist used to saturate diluted brine. The chlorine contains oxygen and must often be purified by liquefaction and evaporation.
Membrane cell procedure – similar to the diaphragm prison cell procedure, with a Nafion membrane to separate the cathode and anode reactions. Only sodium ions and a trivial water laissez passer through the membrane. Information technology produces a higher quality of NaOH. Of the three processes, the membrane jail cell process requires the lowest consumption of electric energy and the amount of steam needed for concentration of the caustic is relatively small (less than one tonne per tonne of caustic soda).

An older method for sodium hydroxide production was the LeBlanc process, which produced sodium carbonate, followed by roasting to create carbon dioxide and sodium oxide. This method is withal occasionally used. Information technology helped to plant sodium hydroxide as an important commodity chemical.

Major producers

In the United States, the major producer of sodium hydroxide is the Dow Chemical Company, which has annual production around three.7 million tonnes from sites at Freeport, Texas, and Plaquemine, Louisiana. Other major Usa producers include Oxychem, PPG, Olin, Pioneer Companies, Inc. (PIONA), and Formosa. All of these companies utilize the chloralkali procedure.

Uses

General applications

Sodium hydroxide is the primary strong base of operations used in the chemic industry. In bulk it is about often handled as an aqueous solution, since solutions are cheaper and easier to handle. It is used to drive for chemical reactions and as well for the neutralization of acidic materials. Information technology tin can be used also as a neutralizing agent in petroleum refining

Experiment

Sodium hydroxide has also been used in conjunction with zinc for creation of the famous "Gold pennies" experiment. A penny is boiled in a solution of NaOH together with some granular zinc metal, the color of the penny will plow argent in nearly 45 seconds. The penny is then held in the flame of a burner for a few seconds and it turns golden. The reason this happens is that granular zinc dissolves in NaOH to course Zn(OH)₄ ^two-. This zincate ion becomes reduced to metallic zinc on the surface of a copper penny. Zinc and copper when heated in a flame form contumely.

Use in chemical analysis

In analytical chemistry, sodium hydroxide solutions are often used to measure the concentration of acids by titration. Since NaOH is not a chief standard, solutions must first exist standardised by titration against a standard such equally KHP. Burettes exposed to NaOH should exist rinsed out immediately after use to prevent "freezing" of the stopcock.

Lather making

Lather making via saponification is the most traditional chemical procedure using sodium hydroxide. The Arabs began producing soap in this manner in the 7th century, and the same bones process is still used today.

Biodiesel

For the manufacture of biodiesel, sodium hydroxide is used every bit a catalyst for the transesterification of methanol and triglycerides. This but works with anhydrous sodium hydroxide, considering water and lye would turn the fat into soap which would be tainted with methanol.

It is used more often than potassium hydroxide because it costs less, and a smaller quantity is needed for the aforementioned results. Another culling is sodium silicate.

Aluminium etching

Strong bases attack aluminium. This tin can be useful in carving through a resist or in converting a polished surface to a satin-like terminate, but without further passivation such as anodizing or allodizing the surface may become corroded, either under normal use or in astringent atmospheric conditions.

Nutrient preparation

Nutrient uses of lye include washing or chemical peeling of fruits and vegetables, chocolate and cocoa processing, caramel colour production, poultry scalding, soft drinkable processing, and thickening water ice cream. Olives are often soaked in lye to soften them, while pretzels and German lye rolls are glazed with a lye solution before blistering to brand them well-baked.

Specific foods candy with lye include:

The Scandinavian effeminateness known as lutefisk (from lutfisk, "lye fish").
Hominy is dried maize (corn) kernels reconstituted past soaking in lye-h2o. These aggrandize considerably in size and may be further processed by cooking in hot oil and salting to course corn nuts. Nixtamal is similar, but uses calcium hydroxide instead of sodium hydroxide.
Hominy is also known in some areas of the Southeastern United States, as the breakfast food grits, dried and basis into a coarse pulverization. They are prepared by boiling in water, with the addition of butter and other ingredient to adjust the tastes of the preparer.
Sodium hydroxide is besides the chemic that causes gelling of egg whites in the production of Century eggs.
German pretzels are poached in a boiling sodium hydroxide solution before baking, which contributes to their unique crust.

Domestic uses

Sodium hydroxide is used in the home as an agent for unblocking drains, provided as a dry crystal (eastward.k. " Drāno") or as a thick liquid gel. The chemical mechanism employed is the conversion of grease to a grade of lather, then forming a water soluble form to be dissolved past flushing; also decomposing complex molecules such every bit the protein of hair. Such drain cleaners (and their acidic versions) are highly caustic and should be handled with care.

Tissue Digestion

This is a process that was used with farm animals at i time. This process involves the placing of a carcass into a sealed chamber, which and so puts the carcass in a mixture of lye and water, which breaks chemical bonds keeping the trunk intact. This eventually turns the body into a coffee-similar liquid, and the but solid remains are bone hulls, which could be crushed between one's fingertips. It is also of note that sodium hydroxide is oft used in the procedure of decomposing roadkill dumped in landfills by animal disposal contractors.

In this framework, sodium hydroxide has besides been used by criminals and serial killers to dispose of their victim's bodies.

Illegal drugs

Considering information technology is a key ingredient in the procedure of making Methamphetamine, it is now incommunicable to purchase pure Sodium hydroxide as a consumer product in the Us. Products containing pure Sodium hydroxide, such as Red Devil, are no longer available for sale. Every bit a result, amateur soapmakers must now purchase Sodium hydroxide in bulk.

Safety

Solid sodium hydroxide or solutions containing high concentrations of sodium hydroxide may crusade chemical burns, permanent injury or scarring, and blindness.

Solvation of sodium hydroxide is highly exothermic, and the resulting oestrus may cause rut burns or ignite flamables.

The combination of aluminium and sodium hydroxide results in a large product of hydrogen gas:
2Al( southward) + 6NaOH(aq) → 3H_ii(g) + 2Na₃AlO₃(aq).
Mixing these ii in a closed container is therefore unsafe.

For more information, consulting an MSDS is suggested.

Trivia

This danger was shown in a scene of the 1999 movie Fight Club, where the character Tyler Durden puts information technology on the protagonist'southward freshly kissed hand to create a lip-shaped scar, symbolizing their commitment to the plan that makes up the movie's plot. This is the but scene in the moving-picture show which Brad Pitt'southward parents accept seen - he showed it to them earlier its release to convince them not to lookout man the movie.
Lye is used equally an assault weapon in an episode of U.s. crime drama CSI: New York, in which the victim has the chemical thrown over his face, causing a chemical burn, and his eventual death.
Mythbusters episode 20 tested the theory that jawbreakers mixed with sodium hydroxide would explode under estrus. They heated solid, dry out sodium hydroxide with jawbreakers in a microwave, finding that the mixture didn't explode earlier the sodium hydroxide itself exploded. Unofficial Mythbusters Guide: Episode 20 It'due south of import to note that solid sodium hydroxide is extremely caustic, therefore it is unlikely to exist found in food.