What are the common dangerous gases in laboratories?

Hydrogen, nitrogen, oxygen, carbon dioxide gas, propane gas, hydrogen sulfide gas, hydrogen chloride gas, chlorine gas, fluorine gas, hydrogen fluoride gas, bromine, hydrogen bromide gas, methane gas.

Common hazardous chemicals in laboratories

1. Explosives: highly explosive. When subjected to external factors such as high-heat friction, impact, vibration, or contact with other substances that conflict with properties, violent chemical reactions will occur, producing a large amount of gas and high heat, causing an explosion. Such as: trinitrotoluene (TNT), picric acid, ammonium nitrate, azide, fulminate and other organic compounds with more than three nitro groups.

2. Oxidizing agent: It has strong oxidizing properties. According to its different properties, it can be mixed with substances that are in conflict with acids, alkalis, moisture, strong heat, or with flammable substances, organic substances, reducing agents and other properties. Decomposes, causing combustion and explosion. Such as: chlorates, nitrates, peroxides, perchloric acid and its salts of alkali metals and alkaline earth metals, permanganates, dichromates, nitrites, etc.

3. Compressed gas and liquefied gas: Gas is compressed and stored in pressure-resistant cylinders, making it dangerous. If a cylinder is exposed to the sun or heated, it can cause an explosion when the pressure inside the cylinder rises above the pressure limit of the container. Gases in cylinders are divided into four categories according to their properties:

Highly toxic gases, such as liquid chlorine, liquid ammonia, etc.

Fflammable gases, such as acetylene, hydrogen, etc.

Combustion-supporting gas, such as oxygen, etc.

Non-flammable gases, such as nitrogen, argon, helium, etc.

4. Self-igniting items: When these substances are exposed to the air, they rely on their own decomposition and oxidation to generate heat, causing their temperature to rise to the self-ignition point to ignite. Such as white phosphorus, etc.

5. Items that burn when exposed to water: They can quickly decompose when exposed to water or in humid air, generate high heat, and release flammable and explosive gases, causing combustion and explosions. Such as metal potassium, sodium, calcium carbide, etc.

6. Flammable liquids: This type of liquid is easily volatilized into gas and will burn when exposed to an open flame. The flash point of flammable liquids is the main basis for assessing the fire hazard of liquids. The lower the flash point, the greater the hazard. Those with a flash point below 45°C are called flammable liquids, and those with a flash point above 45°C are called flammable liquids (flammable liquids are not included in dangerous goods management). Flammable liquids are classified according to their degree of danger:

(1) The flash point of first-class flammable liquids is below 28°C (including 28°C). Such as ether, petroleum ether, gasoline, methanol, ethanol, benzene, toluene, ethyl acetate, acetone, carbon disulfide, nitrobenzene, etc.

(2) The flash point of secondary flammable liquid is 29-45℃ (including 45℃). Such as kerosene, etc.

7. Flammable solids: Such items have a low ignition point. If heated, exposed to sparks, impacted, rubbed or oxidized, they can cause rapid combustion or explosion, and at the same time release a large amount of toxic gases. Such as red phosphorus, sulfur, naphthalene, nitrocellulose, etc.

8. Toxic substances: They are highly toxic and can cause poisoning or even death if a small amount enters the human body or contacts the skin. Such as: mercury and mercury salts (mercuric chloride, mercury nitrate, etc.), arsenic and arsenic compounds (arsenic trioxide, that is, arsenic), phosphorus and phosphorus compounds (yellow phosphorus, that is, white phosphorus, eating 0.1 grams of yellow phosphorus can cause death), aluminum and lead Salt (lead monoxide, etc.), hydrocyanic acid and cyanide (HCN, NaCN, KCN), as well as sodium fluoride, carbon tetrachloride, chloroform, etc.

Toxic gases, such as aldehydes, ammonia, hydrofluoric acid, sulfur dioxide, sulfur trioxide and chromic acid.

9. Corrosive items: They are highly corrosive and can cause chemical burns when in contact with the human body. Some corrosive items have duality and multiplicity. For example, phenol is corrosive, toxic and flammable. Corrosive items include sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, hydrofluoric acid, glacial acetic acid, formic acid, sodium hydroxide, potassium hydroxide, ammonia, formaldehyde, liquid bromine, etc.

10. Carcinogens: such as: polycyclic aromatic hydrocarbons, 3,4-benzopyrene 1,2-benzanthracene, nitrosamines, nitrogen mustard alkylating agents, α-naphthylamine , β-naphthylamine, benzidine, aromatic amines and some inorganic elements, As, Cl, Be, etc. all have obvious carcinogenic effects, so beware of invading the body.

11. Mutagenic items: Such as ethidium bromide (EB), which is highly mutagenic and carcinogenic. Wear disposable gloves when using them, pay attention to operating regulations, and do not touch other items casually.

12. Radioactive items: They are reflective. Excessive exposure to the human body or inhalation of radioactive dust can cause radiation sickness.

Such as: thorium nitrate and radioactive mineral monazite, etc.