HYDROGENSULFIDE Pharmacy grade

Hydrogen sulfide, the formula for H2S, the molecular weight of 34.076, a standard condition is a flammable acidic gas, colorless, low concentration have a rotten egg smell, highly toxic. [1] its aqueous solution for hydrogen sulfate. Molecular weight is 34.08, the vapor pressure of 2026.5 kPa / 25.5 ℃, flash point for < - 50 ℃, the melting point is 85.5 ℃, boiling point is 60.4 ℃, the relative density of air (= 1) 1.19. Soluble in water, soluble in alcohol, solvent oil and crude oil. Flash point is 292 ℃. Hydrogen sulfide is flammable for, mixed with air to form explosive mixture, caused an explosion of the combustion flame, high heat. Hydrogen sulfide is a kind of important chemical raw material.

Physical and chemical properties

Molecular structure, central atom S atomic take sp after hybridization (according to the bond Angle calculation results are close to p after hybridization), electron pair configurations are all fit, molecular configuration for V, H, S, H bond Angle is 92.1 °, 0.97 D, dipole moment is a polar molecule. Because H - S key to weaker, around 300 ℃ h2s decomposition.

Ignition point: 260 ℃, the saturation vapor pressure: 2026.5 kPa / 25.5 ℃, solubility: soluble in water, dissolved ratio 1:2. 6), ethanol, carbon disulfide, glycerin, gasoline, kerosene, etc. [2]. Critical temperature: 100.4 ℃, the critical pressure: 9.01 MPa. [2]

Danger tags: 2.1 type of flammable gas, 2.3 class toxic gas, toxic.

Color and smell [3] : hydrogen sulfide is a colorless, highly toxic, acidic gas. The smell of a special kind of rotten eggs, olfactory threshold: 0.00041 PPM, even a low concentration of hydrogen sulfide, also can damage people's sense of smell. High concentration but no smell (because of high concentration hydrogen sulfide can paralyze olfactory nerve). With his nose as a means of detecting the gas can be deadly.

The relative density of 1.189 (15 ℃, 0.10133 MPa). It exists in the lower level, such as pit, the basement. If it is found that in was told that there are hydrogen sulfide, then it should be immediately self-protection measures. As long as possible, in the direction of the wind, to higher ground. [3]

Explosion limit: with air or oxygen in appropriate proportion (4.3% ~ 46%) would explode. Therefore containing hydrogen sulfide gas existing monitor the job site shall be provided with hydrogen sulfide. [3]

Flammability: completely dry hydrogen sulfide does not react with oxygen in the air at room temperature, but can be in the air when the ignition burning, drilling, downhole operation choke when combustion, the combustion rate is only 86%. Hydrogen sulfide produced in blue flame combustion, and generate toxic sulfur dioxide, sulfur dioxide gas can damage the eyes and lungs. When air is enough, generating SO2 and H2O. [3]

If insufficient or air temperature is low, the generated free S and H2O. [3]

In addition to the oxygen or air, hydrogen sulfide can burn in the presence of chlorine and fluorine.

Solubility: hydrogen sulfide gas is soluble in water, ethanol and glycerol, the chemical properties of instability. Slightly soluble in water, weak acid formation, called a "hydrogen sulfate. Its aqueous solution containing hydrogen sulfate HS - (in 18 degrees Celsius, concentration of 0.01 to 0.01 per liter of solution, pKa = 6.9) and the ion sulfur S (pKa = 11.96). First clear hydrogen sulfate placed after a period of time will become turbid, this is because the hydrogen sulfate and dissolved oxygen in the water on the slow response, insoluble in water elemental sulfur.

Hydrogen sulfide is a kind of binary acid. At 20 ℃ water can dissolve 1 volume 2.6 volume of hydrogen sulfide, generated called hydrogen sulfuric acid aqueous solution, concentration of 0.1 mol/L [3]. Hydrogen sulfide in the water of the second ionization degree is quite low, so that the sodium sulfide concentration of aqueous solution of alkali than sodium hydroxide is slightly lower, can serve as strong base using:

Hydrogen sulfide in solution equilibrium which were as follows:

Hydrogen sulfate than hydrogen sulfide gas has more strong reducibility, easy oxidation by air and sulfur precipitation, make the solution become cloudy. In acidic solution, hydrogen sulfide can make Fe3 + reduction of Fe2 +, Br2 reduction of Br -, I2 reduction as I -, reduction of Mn2 +, reduction of Cr3, +, HNO3 to NO2, which itself is often oxidation of elemental sulfur. [3] H2S can also restore solution of copper ions (Cu2 +), selenite (H2SeO3), tetravalent polonium (Po4 +) ions, etc., such as:

Hydrogen sulfide gas and metal to produce the precipitation, often removed using sedimentary, removal of hydrogen sulfide gas in the laboratory, the method used is the hydrogen sulfide gas into the copper sulfate solution, the formation of insoluble from general acid copper sulfide (non oxidizing acid) :

But if hydrogen sulfide and ferric sulfate reaction, reduce the quantity of hydrogen sulfide can only generate elemental sulfur, because Fe3 + and S2 - REDOX reaction will happen:

Note: hydrogen sulfide sulfur is - 2 price, at the lowest price. But hydrogen is + 1 price, price can drop to zero, so there is still a oxidation, such as:

Hydrogen sulfide can occur to response:

The hydrogen sulfide is a reducing agent, sulfur dioxide is antioxidant, sulfur is oxidation products.

Main use edit

Used for synthesis of phosphor powder, electric light, the light conductor, photoelectric exposure meter manufacturing, etc. Reducing agent in organic synthesis. Used in metal refining, pesticide, medicine, catalyst regeneration. General reagents. Making all kinds of sulfide.

Used in the manufacture of inorganic sulfide, also used for chemical analysis of metal ions, such as identification. [2]