氫氧化鈉 NaOH固體溶于水放熱；又稱燒堿、火堿、苛性鈉，是常見的、重要的堿，英文名稱sodiun hydroxide（別名Caustic soda）。 化學式NaOH 式量40.01。密度2.130克/厘米3，熔點318.4℃，沸點1390℃。純的無水氫氧化鈉為白色半透明，結晶狀固體。

NaOH solid solution in water exothermic; also known as caustic soda, caustic soda, caustic soda, is a common and important alkali, English name sodium hydroxide (alias calcium soda). The amount of NaOH is 40.01. 130 g / cm3, melting point 318. 4 ℃, boiling point 1390 ℃. Pure anhydrous sodium hydroxide is white, translucent, crystalline solid.

氫氧化鈉極易溶于水，溶解度隨溫度的升高而增大，溶解時能放出大量的熱。它的水溶液有澀味和滑膩感，溶液呈強堿性，具備。氫氧化鈉的用途十分廣泛，在化學實驗中，除了用做試劑以外，由于它有很強的吸濕性，還可用做堿性干燥劑。燒堿在國民經濟中有廣泛應用，許多工業部門都需要燒堿。使用燒堿多的部門是化學藥品的制造，其次是造紙、煉鋁、煉鎢、人造絲、人造棉和肥皂制造業。

Sodium hydroxide is easily soluble in water, and its solubility increases with the increase of temperature. When it dissolves, it can release a lot of heat. Its aqueous solution is astringent and greasy, the solution is strong alkaline, with good taste. Sodium hydroxide is widely used in chemical experiments. In addition to being used as a reagent, it can also be used as an alkaline desiccant because of its strong hygroscopicity. Caustic soda is widely used in the national economy, many industrial sectors need caustic soda. The sectors that use caustic soda most are chemical manufacturing, followed by papermaking, aluminum smelting, tungsten smelting, rayon, artificial cotton and soap manufacturing.

另外，在生產染料、塑料、藥劑及有機中間體，舊橡膠的再生，制金屬鈉、水的電解以及無機鹽生產中，制取硼砂、鉻鹽、錳酸鹽、磷酸鹽等，也要使用大量的燒堿。工業用氫氧化鈉應。>>在工業上，氫氧化鈉通常稱為燒堿，或叫火堿、苛性鈉。

In addition, in the production of dyes, plastics, chemicals and organic intermediates, the regeneration of old rubber, the electrolysis of metal sodium and water, and the production of inorganic salts, a large amount of caustic soda is also used in the production of borax, chromate, manganate, phosphate, etc. Sodium hydroxide for industrial use should be used. >>In industry, sodium hydroxide is usually called caustic soda, or caustic soda.

這是因為較濃的氫氧化鈉溶液濺到皮膚上，會腐蝕表皮，造成燒傷。它對蛋白質有溶解作用，有強烈刺激性和腐蝕性。用0.02%溶液滴入兔眼，可引起角膜上皮損傷。小鼠腹腔內LD50: 40 mg/kg，兔經口LDLo: 500 mg/kg。粉塵刺激眼和呼吸道，腐蝕鼻中隔；濺到皮膚上，尤其是濺到粘膜，可產生軟痂，并能滲入深層組織，灼傷后留有瘢痕。

This is because the concentrated sodium hydroxide solution splashed on the skin will corrode the epidermis and cause burns. It dissolves proteins and has strong irritation and corrosiveness. 0.02% solution can cause corneal epithelial damage. Oral administration of LD50 mg / kg in rabbits and intraperitoneal administration of LD50 mg / kg in mice. Dust can irritate eyes and respiratory tract, corrode nasal septum; when it splashes on skin, especially mucous membrane, it can produce soft scab and penetrate deep tissue, leaving scar after burn.