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水是最常见的灭火剂,但由于化学物质的特殊性,有些物质起火后不能用水去扑救,具休说有以下几类物质: 一、遇水燃烧的物质:如金属钾、钠等,当遇水后即发生剧烈的化学反应,放出氢气,同时放出大最热,从而引起燃烧或爆炸。 二、比重小于水且不溶于水的易燃液体:如汽油、乙醚、苯等均不能用水扑救。因为这些物质比重比水轻,如果用水灭火,它会漂浮在水面上随水的流动使火势蔓延开来。 三、易燃粉状固体:如铝粉、镁粉、闪光粉等不能直接用水扑救,避免粉尘被冲散在空气中形成爆炸性混
Water is the most common fire extinguishing agent, but because of the special nature of the chemical substances, some substances can not be extinguished by water after a fire. There are several types of substances to be disclosed: 1. Materials that react with water: metals such as potassium and sodium, After the water occurs violent chemical reaction, release hydrogen, at the same time release the hottest, causing combustion or explosion. Second, the proportion of less than water and insoluble in flammable liquids: such as gasoline, ether, benzene, etc. can not use water to fight. Because these substances are lighter than water, if water is used to extinguish the fire, it floats on the surface of the water and spreads with the flow of water. Third, the flammable powdery solid: such as aluminum, magnesium, flash powder, etc. can not be directly saved with water to prevent the dust is dispersed in the air to form explosive mixed