1、 Different definitions

（1）焦亚硫酸钠为白色或黄色结晶粉末或小结晶，带有强烈的SO2气味，比重 1.4，溶于水，水溶液呈酸性，与强酸接触则放出SO2而生成相应的盐类， 久置空气中，则氧化成Na2S2O6，故该产品不能久存。高于150摄氏度，即*解出SO2。

(1) Sodium pyrosulfite is a white or yellow crystalline powder or small crystal, with a strong smell of SO2, with a specific gravity of 1.4. It is soluble in water, and the aqueous solution is acidic. In contact with strong acid, SO2 will be released to generate corresponding salts. If it is placed in the air for a long time, it will be oxidized to na2s2o6, so the product cannot exist for a long time. Above 150 ℃, i.e. * SO2 is decomposed.

（2）亚硫酸钠，又称无水亚硫酸钠、化学式Na2SO3，常见的亚硫酸盐，白色、单斜晶体或粉末。对眼睛、皮肤、粘膜有刺激作用，可污染水源。

(2) Sodium sulfite, also known as anhydrous sodium sulfite, chemical formula Na2SO3, common sulfite, white, monoclinic crystal or powder. It can irritate eyes, skin and mucous membrane and pollute water sources.

受高热*解产生有毒的硫化物烟气。工业上主要用于制亚硫酸纤维素酯、硫代硫酸钠、化学药品、漂白织物等， 还用作还原剂、防腐剂、去氯剂等。

Toxic sulfide flue gas is produced by high thermal decomposition. In industry, it is mainly used to make cellulose sulfite, sodium thiosulfate, chemicals, bleached fabrics, etc. it is also used as reducing agent, preservative, dechlorinating agent, etc.

二、颜色、形状不同

2、 Different colors and shapes

（1）焦亚硫酸钠为白色或黄色结晶粉末或小结晶。

(1) Sodium pyrosulfite is white or yellow crystalline powder or small crystals.

（2）亚硫酸钠：常见的亚硫酸盐，白色、单斜晶体或粉末。

(2) Sodium sulfite: common sulfite, white, monoclinic crystal or powder.

三、作用不同

3、 Different functions

（1）医药工业用于生产氯仿、苯丙砜和苯甲醛。橡胶工业用作凝固剂。印染工业用作棉布漂白后的脱氯剂、棉布煮炼助剂。制革工业用于皮革处理，能使皮革柔软、坚韧，具有防水、抗折、耐磨等性能。化学工业用于生产羟基香草醛、盐酸羟胺等。感光工业用作显影剂等。

(1) The pharmaceutical industry is used to produce chloroform, phenylpropanesulfone and benzaldehyde. The rubber industry is used as a coagulant. Printing and dyeing industry is used as dechlorination agent for cotton bleaching and cotton scouring assistant. Leather industry is used for leather treatment, which can make leather soft and tough, with waterproof, folding resistance, wear resistance and other properties. Chemical industry is used to produce hydroxyvanillin, hydroxylamine hydrochloride, etc. Photosensitive industry is used as developer, etc.

（2）用于碲和铌的微量分析测定和显影液的配制，还用作还原剂；用于人造纤维稳定剂、织物漂白剂、照相显影剂、染漂脱氧剂、香料和染料还原剂、造纸木质素脱除剂等；用作普通分析试剂和电阻材料。

(2) It is used for microanalysis and determination of tellurium and niobium and preparation of developing solution. It is also used as reducing agent; It is used as stabilizer for man-made fiber, fabric bleach, photographic developer, deoxidizer for dyeing and bleaching, reducing agent for perfume and dye, lignin remover for papermaking, etc; Used as common analytical reagent and resistance material.