Basic information about the chemical properties of H2S. How it reacts with chemical substances for applications in various industries.
H2S gas is very toxic to humans, animals, plants, and the environment. Although it is a colorless gas, it has a very unpleasant odor (described as the smell of rotten eggs).
This gas is released into the atmosphere in significant quantities each year from both natural and man-made sources.
What is H2S, basic information about H2S gas:
What is H2S?
♦ H2S gas, or hydrogen sulfide gas, is colorless, has a rotten egg odor, and is heavier than air (d ≈ 1.17). It liquefies at −60°C and solidifies at −86°C.
♦ Is H2S soluble in water? H2S gas can dissolve in water, with a solubility S = 0.38 g/100g H2O at 20°C and 1 atm.
Properties of H2S – hydrogen sulfide
Below are some properties of H2S
- H2S gas is colorless and heavier than air
- It is a gas with an unpleasant rotten egg odor and is very toxic.
- The molecular structure of H2S is similar to the molecular structure of water (H2O) in that both are polar.
- However, H2S has a weaker ability to form hydrogen bonds than water. H2S gas is sparingly soluble in water but readily soluble in organic solvents.
>>>>>> See more: What is H2S – hydrogen sulfide?
Origin of hydrogen sulfide gas, where does H2S gas come from:
H2S gas is found both naturally and produced industrially:
Natural sources of H2S
Hydrogen sulfide gas is formed by the decomposition of organic matter, rotting vegetation, especially in shallow water areas, coastlines, and shallow rivers and lakes.
This gas is found to be released from volcanic fissures, sewers, deep wells, and coal mines. It is estimated that 50-60 million tons of H2S gas are produced naturally each year.
Produced in industrial processes
♦ H2S is produced industrially from processes using sulfur-containing fuels. During the processing of cellulose, artificial fiber production, paper pulping, leather tanning, dye manufacturing, and wastewater treatment….
♦ The estimated amount of H2S gas produced in industrial processes is about 3 million tons per year.
Chemical properties of H2S, characteristics of hydrogen sulfide:
Chemical properties of H2S – hydrogen sulfide
H2S is acidic: Chemical properties of H2S
The first chemical property of H2S that we want to mention is that H2S is a weak acid.
♦ Hydrogen sulfide gas can dissolve in water, as mentioned above, and forms a very weak acid solution called hydrosulfuric acid, which is even weaker than carbonic acid.
♦ Hydrosulfuric acid reacts with alkaline solutions to form two types of salts: neutral salts and acid salts.
H2S acid has strong reducing properties
A characteristic chemical property of hydrogen sulfide is its strong reducing property, which is the second chemical property of H2S that we need to discuss.
Because in the H2S molecule, sulfur has the lowest oxidation state (-2), it is a strong reducing agent that can react with most oxidizing agents to produce products with higher oxidation states. In the H2S compound, the oxidation number of the sulfur element is at its lowest level of -2.
Depending on the nature and concentration of the oxidizing agent involved in the chemical reactions, as well as the temperature, the sulfur element can be oxidized to free sulfur (S0). Or it can be converted to sulfur with an oxidation number of +4 (S+4), or sulfur with an oxidation number of +6 (S+6).
Reactions of H2S
H2S gas reacting with O2 can produce S or SO2 depending on the reaction conditions and the amount of oxygen:
♦ 2H2S + 3O2 → 2H2O + 2SO2 (if oxygen is in excess)
♦ 2H2S + O2 → 2H2O + 2S
At high temperatures, H2S gas will burn in the air with a pale blue flame, and H2S is oxidized to SO2:
♦ 2H2S + 3O2 -> 2H2O + 2SO2
When reacting with chlorine, H2S can produce S or H2SO4 depending on the reaction conditions:
♦ H2S + 4Cl2 + 4H2O → 8HCl + H2SO4
♦ H2S + Cl2 → 2 HCl + S (chlorine gas reacts with H2S gas)
H2S solution is a weak acid in two stages: When reacting with alkaline solutions, it can form acid salts or neutral salts
♦ H2S + NaOH → NaHS + H2O
♦ H2S + 2NaOH → Na2S + 2H2O
Common methods of preparing H2S:
Preparing H2S from natural sources
♦ This gas is mostly produced naturally and as a byproduct of industrial processes, as mentioned above. Hydrogen sulfide is often prepared from the microbial decomposition of organic matter in the absence of O2 (also known as anaerobic decomposition)
♦ H2S is also found in volcanic gases and natural gas
Preparing H2S in the laboratory
♦ In the laboratory, this gas is prepared by reacting hydrochloric acid solution with iron(II) sulfide:
♦ FeS + 2HCl → FeCl2 + H2S↑
♦ Or preparing H2S from S
♦ Some metal and nonmetal sulfides react with water to produce hydrogen sulfide
Preparing H2S in industry
H2S is produced when separating it from sour gas – natural gas with a high H2S content. It can also be produced by reacting hydrogen with molten elemental sulfur at around 450 °C.
H2S gas harmful to humans and how to prevent it
- H2S is an asphyxiant gas because it is heavier than air and displaces oxygen.
- Inhalation can cause asphyxiation.
- H2S acid affects the eyes, causing conjunctivitis.
- It affects the lungs, causing pulmonary edema due to lack of oxygen, and can cause rapid breathing and respiratory arrest, leading to death if present at high concentrations.
The rotten egg smell of H2S gas is easily recognizable, so it is also easy to avoid. You should not work for long periods in places that generate a lot of H2S gas.
In hot and humid environments, H2S gas can be oxidized and combine with water vapor in the air to form tiny droplets of sulfuric acid, which can enter the lungs and lymphatic system, causing congestion and discomfort.
However, H2S gas is also used in many different industrial production and processing sectors. If you are looking to learn more about or purchase high-quality pure H2S gas, please call MIGCO for detailed advice.
See more: http://migco.vn/khi-h2s/
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