Sodium hydroxide
Sodium hydroxide (NaOH), commonly known as caustic soda, caustic soda, caustic soda, caustic soda by another name in Hong Kong as caustic soda, room temperature is a white crystal, with a strong corrosive. Soluble in water, its aqueous solution is strongly alkaline, can phenolphthalein red. Sodium hydroxide is a very popular base, is one of the chemical laboratory of the essential drugs. It can be used as washing liquid solution.
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About the control information of sodium hydroxide
Name
Chemical formula
Molecular weight
Characters
Save
Use
Security measures
Basic information
NaOH features
Use NaOH
NaOH industrial system of law
Produced a small amount of sodium hydroxide
Precautions for use and storage
Technical indicators of solid sodium hydroxide
NaOH impact on the environment a health hazard
Two, toxicology information and environmental behavior
NaOH emergency treatment and disposal methods a leakage contingency
Second, the protective measures
Third, first-aid measures
Introduction to the chemical nature of sodium hydroxide NaOH regulatory information
Name
Chemical formula
Molecular weight
Characters
Save
Use
Security measures
Basic information
NaOH features
Use NaOH
NaOH industrial system of law
Produced a small amount of sodium hydroxide
Precautions for use and storage
Technical indicators of solid sodium hydroxide
NaOH impact on the environment
A health hazard two, toxicology information and environmental behavior of emergency treatment and disposal methods NaOH
A leakage contingency Second, the three protective measures, emergency measures to expand the chemical properties of NaOH, sodium hydroxide Profile Edit this paragraph
Regulatory information
Sodium hydroxide (corrosion) of the goods under the “Precursor Chemicals Management Regulations” by the public security departments control.
Name
Chinese name: sodium hydroxide Chinese Synonyms: caustic soda, caustic soda, caustic soda
Chemical formula
NaOH
Molecular weight
40.00
Characters
Melt white granules or strips, are often made of small pieces. Easy to absorb moisture and carbon dioxide in the air. 1g dissolved in 0.9ml water, 0.3ml boiling water, 7.2ml of anhydrous ethanol, 4.2ml of methanol, soluble in glycerol. Soluble in water, ethanol or mixed with acid solution generated when the intense heat. Showed a strong alkaline solution. The relative density of 2.13. Melting point 318 ℃. Boiling point 1390 ℃. Median lethal dose (mice, ip) 40mg/kg. Corrosive.
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Sealed in dry place.
Use
Widespread application of the basic analytical reagent. Preparation of standard alkali. A small amount of carbon dioxide and moisture absorbent. Acid neutralization. Sodium salt manufacturing.
Security measures
Airtight packaging, storage in a cool dry place. And acids, easy (may) Equal combustible storage sub-delivered. Skin (eye) contact, mobile water rinse. Ingested, rinse mouth with water, drink milk or egg white.
Edit this paragraph the basic information
Chemical formula: NaOH (commonly known as caustic soda, caustic soda, caustic soda, caustic soda) Chinese pronunciation: qīng yǎng huà nà (shaojian) sodium hydroxide Enlargement
English name: Sodium Hydroxide English nickname: Sodium Hydrate, Caustic Soda, Lye (liquid) Molecular weight: 40.01 Molecular Weight: 40g/mol CASRN :1310-73-2 EINECS Registry Number :215 -185-5 density: 2.130 g / cm ³ ; melting point: 318.4 ℃ water solubility: easily soluble in boiling water solution was colorless: 1390 ℃ base dissociation constant (Kb) = 3.0 reciprocal base dissociation constant logarithmic (pKb) = -0.48 lethal dose: 40mg/kg hydroxide secondary identification sodium method: adding MgCl2, produce white precipitate. Flame reaction, the flame yellow.
Edit this paragraph NaOH features
There is a strong corrosive, water absorption, can be used as desiccant, however, can not dry and sulfur dioxide, carbon dioxide, nitrogen dioxide and hydrogen chloride and other acid gases. (Reaction with acid gases.) And deliquescent in the air and liquid (water and dissolved by the phenomenon, is a physical change); soluble in water, and release a lot of heat. Can phenolphthalein red, blue to purple litmus test solution, are strong bases. Corrosive to aluminum material, non-corrosive plastic. Just a few minutes on the air, it will absorb moisture and become liquid poison. Its melting point is 318.4 ℃. In addition to soluble in water, the sodium hydroxide is also soluble in ethanol, glycerol; but insoluble in ether, acetone, liquid ammonia. The fluid is a colorless, liquid astringency and a greasy feel. Sodium hydroxide and carbon dioxide in the air response may degenerate 2NaOH + CO2 ==== Na2CO3 + H2O Sodium (Na) reacts with water (reaction with water, apply the beaker and the beaker sealed glass, reaction time block sodium floating on the water, melting into a ball, swim in the water, the “hissing” sound, and resultant splash), generate strong alkaline NaOH solution NaOH crystals enlarge
And release hydrogen. Solid NaOH to OH in the OH covalent bond, Na and OH to strong ionic binding, soluble in water dissociation degree of close to 100%, so the solution is strongly alkaline, colorless phenolphthalein test solution can turn red , or the PH test paper, litmus solution, such as purple and blue. Pure anhydrous sodium hydroxide is white translucent, crystalline solid. Sodium hydroxide soluble in water, solubility increases with increasing temperature, dissolved a lot of heat when released, 288K up when the concentration of its saturated solution 16.4mol / L (1:1). It has astringent and a greasy feel aqueous solution, the solution is strongly alkaline, with acid reaction, with all the continuity of alkali. Commercial solid and liquid caustic soda are two types: pure white solid caustic soda, a block, sheet, rod-like, granular, friable; pure liquid caustic soda is colorless and transparent liquid. Sodium hydroxide is also soluble in ethanol, glycerol; but insoluble in ether, acetone, liquid ammonia. Fiber, skin, glass, ceramics and other corrosive effect, dissolved or diluted concentrated solution will release heat; and occurs in the inorganic acid and the reaction can also produce a lot of heat, generates the corresponding salts; with aluminum and zinc, non-metallic release reaction of boron and silicon, hydrogen; with chlorine, bromine, iodine and other halogen disproportionation reaction. Precipitation of metal ions from aqueous solution as hydroxides; can grease saponification reaction occurs to produce the corresponding sodium salt of organic acids and alcohols, which is to remove the oil on the principle of the fabric. Note: Sodium hydroxide out on the air as long as it will quickly absorb the liquid water molecules become toxic.
Edit NaOH purposes of this paragraph
Extensive use of sodium hydroxide in the chemical experiment, in addition to other reagents used, because it has a strong water absorption, can be used as basic desiccant. Sodium hydroxide is widely applied in the national economy, many industries need to sodium hydroxide. Sodium hydroxide is used the most chemicals manufacturing sector, followed by paper, aluminum, tungsten refining, rayon, rayon and soap manufacturing. In addition, in the production of dyes, plastics, pharmaceutical and organic intermediates, the regeneration of the old rubber, metal sodium, water electrolysis and the salt production, preparation of borax, chromium salt, potassium permanganate, phosphate, etc., but also to use a large number of caustic soda. Sodium hydroxide for industrial use should meet the national standard GB 209-2006; industrial ion-exchange membrane caustic soda should meet the national standard GB / T 11199-89; chemical sodium hydroxide should be consistent with national standards GB 11212-89; consumption of hydrogen sodium oxide shall meet the national standard GB 5175-85. Photosynthetic carbon dioxide experiment. In industry, often referred to as caustic soda, sodium hydroxide, or caustic soda is called, caustic soda. This is because the darker the sodium hydroxide solution spilled on the skin, will corrode the skin, causing burns. Dissolution of its proteins, there is a strong irritant and corrosive (due to their bags of goods on the eggs NaOH
Dissolution of white matter, compared with acid burns, alkali burns more difficult to heal.) Dropping by 0.02% solution of rabbit eyes, can cause corneal epithelial damage. Intraperitoneal LD50: 40 mg / kg, rabbit oral LDLo: 500 mg / kg. Dust irritate the eye and respiratory tract, erosion of nasal septum; splashed on the skin, especially mucous membrane splash, can produce soft crust, and can penetrate deep tissue, leaving scars after burns; splash in the eyes, not only damage the cornea, but also make deep eye tissue damage, severe cases can cause blindness; Coverage can cause gastrointestinal burns, colic, mucosal erosion, vomiting, stomach contents bloody, bloody diarrhea, and sometimes occurs Sheng Ya, difficulty swallowing, shock, gastrointestinal perforation, the stomach may occur late intestinal stenosis. Due to the strong alkaline, can cause pollution of water bodies, on plants and aquatic organisms should be noted.
Edit this paragraph NaOH industrial production method
A: (1) filtered seawater (2) by adding excess sodium hydroxide to remove calcium and magnesium ions, filtered Ca2 + +2 OH? = Ca (OH)? ↓ (Ca (OH) 2 slightly soluble, can appear turbidity) Mg2 + +2 OH? = Mg (OH)? ↓ (3) use of reverse osmosis membrane production technology out of salt water in the SO? 2? (4) adding an excess of sodium carbonate to remove calcium ions, excess barium ions, filtered Ca2? + CO ? 2? = CaCO? ↓ Ba2? + CO? 2? = BaCO? ↓ (5) by adding appropriate amount of hydrochloric acid to remove excess carbonate ion 2H? + CO? 2? = CO? ↑ + H? O (6) heat get rid of carbon dioxide (7) into the ion exchange column to further remove the calcium and magnesium ions (8) electrolytic electrolytic 2NaCl +2 H2O == == H? ↑ + Cl? ↑ +2 NaOH
Edit this paragraph produced a small amount of sodium hydroxide
You can find some sodium bicarbonate (baking soda) (better if sodium carbonate), find more of calcium oxide (lime) (food packaging generally used for water absorbent have a small bag, such as seaweed package ah something). Put the lime in the water after reaction into a stone mortar, the sodium bicarbonate (or sodium carbonate) solid particles (concentrated solution is also OK) by adding lime in order to ensure the purity of the product sodium hydroxide is required to make excessive lime reasons: reference calcium hydroxide and sodium carbonate solubility. Stirring speed up its response, wait until the reaction after a while, put it aside for a moment, with the precipitation of calcium carbonate, sodium hydroxide supernatant is carefully poured can be. If you need a moment of pure point can be heated, part of the water evaporates, which can be relatively pure sodium hydroxide. CaO + H2O ==== Ca (OH) 2 NaHCO3 + Ca (OH) 2 ==== CaCO3 ↓ + NaOH + H2O Ca (OH) 2 + Na2CO3 ==== CaCO3 ↓ +2 NaOH 2Na +2 H2O ==== 2NaOH + H2 ↑
Edit this paragraph precautions for use and storage
Sodium hydroxide, a corrosive
? “Chemical Safety Management of Dangerous Goods Ordinance (February 17, 1987 the State Council)”, “Chemical Safety Management of Dangerous Goods Regulations Ordinance (of Labour [1992] No. 677)”, “the provisions of the workplace safe use of chemicals ( [1996] No. 423 Ministry of Labor) “and other regulations for the safe use of hazardous chemicals, production, storage, transport, handling, etc. are made by the corresponding provisions;” commonly used classification of dangerous chemicals and signs (GB 13690-92 ) “the substance classified in category 8.2 alkaline corrosive substances;” diaphragm caustic soda production and technical regulations (HGA001-83) “,” mercury technical regulations on production of caustic soda (HGA002-83) “special provisions were made. Come in contact with caustic soda should wear protective equipment, work clothes or work cloth cap or appropriate application of synthetic materials. Work operator must wear overalls, face masks, protective glasses, rubber gloves, rubber aprons, rubber boots and other long-barreled PPE. Should be painted a neutral and hydrophobic ointment on the skin. When contact with caustic soda flake or granular, in the workplace should be ventilation, indoor air, the maximum allowable concentration for the Chinese MAC 0.5 mg / m (as NaOH), the United States ACGIH TLVC 2 mg / m 3. Possible exposure to dust, must wear headgear electric powered air purifying respirators and dust. When necessary, wear breathing apparatus. The operator must go through specialized training, strict compliance with operating procedures. Proposed operators wear headgear electric powered air purifying respirators and dust, wear rubber acid suit, wear rubber gloves, acid and alkali. Away from flammable and combustible materials. To avoid dust. Avoid contact with acid. Handling of light when light unloading, packaging and containers to prevent damage. Equipped with emergency equipment leakage. Empty containers may remain hazardous materials. If you want to maintain a solid sodium hydroxide required to put it in a sealed container with desiccant. Dilution or preparation of the solution should be the base is added to water to avoid boiling and splashing. Handling the spill should wear protective glasses and gloves, sweep slowly down to a lot of water, ground water rinse, diluted sewage into the wastewater system. Lye contact with skin, can be 5 to 10% magnesium sulfate solution to clean; if splashed into eyes, immediately wash with large amounts of boric acid aqueous solution; a small amount of ingested immediately with vinegar, 3 to 5% acetic acid or 5% hydrochloric acid, a large number orange or lemon juice, etc and, to drink egg white, milk or vegetable oil and quickly for medical treatment, contraindications emetic and gastric lavage. NaOH crystal morphology
Solid sodium hydroxide can be loaded into 0.5 mm thick steel drums in the strict closure, barrel weight does not exceed 100 kg; plastic bags or brown paper bag outside the second floor in the full opening or openings drums; thread mouth bottle, Lid pressure port glass bottles, plastic bottles or metal (cans) outside the ordinary wooden box; thread mouth bottle, plastic bottle or tin-plated sheet steel barrel (can) take full floor grid boxes, fibreboard or plywood boxes; tinplate drum (cans), metal (cans), plastic bottles, or outside the corrugated metal hose. Containers to be complete, sealed, there should be a clear “corrosive substance” signs. Rail transportation, steel drums available gondola transport. Time of shipment to complete packaging, loading should be safe. During transport to ensure that the container does not leak, did not fall, do not fall, no damage, moisture and rain. Containers found rust, cracks, holes and other phenomena of melting Tangshui, immediately replace the use of packaging or early shipments, containers, tin solder can damage repair. With flammable or combustible material is prohibited, acids, food chemicals and other mixed mixed operation. Transport The transport vehicles should be equipped with emergency equipment leakage. Shall not flammable and acid during storage or shipment. Fire, water, sand and all kinds of fire extinguishers to fight the blaze, but fire fighters should be noted that after the corrosive caustic soda dissolved in water.
Edit this paragraph, the technical indicators of solid sodium hydroxide
Sodium hydroxide indicators project
Indicators of the actual target actual target actual target actual
Sodium hydroxide NaOH ≥ 99.0 99.30 98.0 98.80 96.0 96.50 95.0 95.8
Sodium carbonate Na2CO3 ≤ 0.90 0.40 1.0 0.5 1.4 0.50 1.6 0.70
Sodium chloride NaCl ≤ 0.15 0.03 0.6 0.2 2.8 2.60 3.2 3.1
Iron oxide Fe2O3 ≤ 0.005 0.002 0.008 0.003 0.01 0.003 0.02 0.003
Save chemical laboratory to the attention of the solid sodium hydroxide reagent bottle seal to prevent exposure to the air or absorb water and carbon dioxide deliquescence reaction. Salt solution by electrolysis of caustic soda, or sodium carbonate with milk of lime was obtained by. NaOH modification: 2NaOH + CO ?==== Na? CO? + H? O (so can not use it dry CO?, SO?, H? S and HCl gas) test whether the deterioration NaOH: 1. Dropwise dilute hydrochloric acid Na ? CO? + 2HC l ==== 2NaCl + H? O + CO? ↑ have 2 bubbles are bad. adding calcium hydroxide Na? CO? + Ca (OH )?==== CaCO? ↓ + 2NaOH produce white precipitate is the deterioration 3. add calcium chloride Na? CO? + CaCl ?==== CaCO? ↓ + 2NaCl NaOH produced a white precipitate is the modification can also remove oil, grease hoods can be with its good removal, this process is the alkaline hydrolysis of oil to produce high fatty acid salts and glycerin (glycerol), also known as saponification reaction!
Edit this paragraph, the environmental impact of NaOH
A health hazard
Bottled NaOH
Pathways: inhalation, ingestion. Health Hazard: This product has a strong incentive and corrosive. Dust or fumes can irritate the eyes and respiratory tract, nasal septum erosion; skin and eyes with NaOH direct contact will cause burns; oral intake can cause digestive tract burns, mucous membrane erosion, bleeding and shock.
Two, toxicology information and environmental behavior
Hazardous characteristics: This product does not burn a lot of water and steam heat to form a corrosive solution. The occurrence and reaction with acid and heat. With corrosion. Combustion (decomposition) products: Toxic fumes may be harmful.
Edit this paragraph NaOH emergency treatment and disposal methods
A leakage contingency
Isolation leakage polluted area, located around the warning signs, the proposed emergency personnel wearing gas masks, wearing chemical protective clothing. Do not direct contact with the spill, with clean shovel collection in a dry clean covered containers in a small amount of NaOH added a lot of water, adjusted to neutral, then into the wastewater system. Can also use a lot of water rinse, diluted Add Water Wastewater System. If large spills, recycling or collection of goods bagged sound NaOH
Waste treatment.
Second, the protective measures
Respiratory protection: wear protective masks when necessary. Eye protection: Wear protective chemical safety glasses. Protective clothing: wearing overalls (anti-corrosion material). Hand protection: wear rubber gloves. Other: work, take a shower. Pay attention to personal hygiene.
Third, first-aid measures
Skin contact: rinse immediately with plenty of water, then coated with 3% -5% of the boric acid solution. Eye contact: immediately filed eyelid, mobile or saline irrigation water for at least 15 minutes. Or rinse with 3% boric acid solution. Medical treatment. Inhalation: rapidly from the scene to fresh air. Artificial respiration when necessary. Medical treatment. Ingestion: as soon as possible with things like protein toxic clean the mouth, such as milk, yogurt and other milk quality items. Patients immediately clear mouthwash, oral administration of diluted vinegar or lemon juice, a doctor. Fire fighting methods: mist of water, sand, carbon dioxide fire extinguisher.
Edit this paragraph, the chemical properties of NaOH
1, NaOH is a strong base, with a base of all gender. Standard sodium hydroxide titration
(1) in aqueous solution, ionizing a large number of OH?: NaOH = Na? + OH? (2) energy and acid reaction, NaOH + HCl = NaCl + H2O (3) energy and some acidic oxide reaction, 2NaOH + SO2 ( less than )==== Na2SO3 + H2O NaOH + SO2 (excessive )==== NaHSO3 ① (① generated Na2SO3 and water and excessive reaction of the SO2 NaHSO3) 2NaOH + SO3 ==== Na2SO4 + H2O 2NaOH +3 NO2 = === 2NaNO3 + NO + H2O (4) sodium hydroxide solution and aluminum reaction, 2Al + 2NaOH +2 H2O ==== 2NaAlO2 +3 H2 ↑ (and, in less than the amount of NaOH when the reaction is 2Al +6 H2O === (NaOH) === 2Al (OH) 3 ↓ + 3H2 ↑) (5) Preparation of weak base can be alkali, NaOH + NH4Cl ==== NaCl + NH3 · H2O (6) can and some salt reaction, 2NaOH + CuSO4 === Cu (OH) 2 ↓ + Na2SO4 (7) NaOH is highly corrosive. (8) NaOH to absorb carbon dioxide. Reaction process is as follows: 2NaOH + CO2 ==== Na2CO3 + H2O (CO2 few) NaOH + CO2 ==== NaHCO3 (CO2 excess) (9) NaOH with silica reaction, SiO2 + 2NaOH ==== Na2SiO3 + H2O ( Therefore, the stopper and glass bottles and sticky and difficult to open) (10) can react with the indicator continuity 』『 base case of colorless phenolphthalein red (too thick sodium hydroxide also cause fading of phenolphthalein), met purple Blue litmus test solution (11) on the air, easy deliquescence. It should be placed in a dry environment can also be used to dry gases.
