Key Chemical Properties and Uses of Hydrogen Sulfide
In the year 1777, a German and Swedish Pomeranian pharmaceutical chemist Carl Wilhelm Scheele discovered the chemical composition of hydrogen sulfide (H2S).
H2S chemical name is hydrogen sulfide. It is made of hydrogen and sulfur (H2 and S, respectively). The symbol of hydrogen sulfide is H2S.
H2S is a colourless chalcogen hydride gas with the prevalent foul smell of rotten eggs. It is a poisonous, corrosive, and flammable gas.
Every now and again, hydrogen sulfide is set up by the microbial breakdown of natural (organic) matter without oxygen gas, as in bogs and sewers. This interaction is usually called anaerobic absorption, which is performed by sulfate-reducing microorganisms.
On this page, we will understand more about hydrogen sulfide, its preparation, properties, and uses in detail.
Do You Know?
The British English spelling of the H2S compound name is hydrogen sulphide; however, this spelling is not accepted by the International Union of Pure and Applied Chemistry (in short, IUPAC) or the Royal Society of Chemistry.
Hydrogen Sulfide Properties
Hydrogen sulfide is an exceptionally harmful and combustible, dull gas with a trademark scent of spoiled eggs. It is utilized in the assembling of synthetic compounds, in metallurgy, and as an insightful reagent. It is heavier than air and will in general collect at the lower part of inadequately ventilated spaces. Albeit impactful from the start, it rapidly stifles the feeling of smell.
Hydrogen sulfide happens normally in rough oil, petroleum gas, volcanic gases, and underground aquifers. It can likewise result from the bacterial breakdown of natural matter. It is likewise created by human and creature squanders.
Hydrogen sulfide is utilized in the production of synthetic compounds, in metallurgy, and as an analytical reagent. A few properties of H2S compound name are as follows:
Properties of H2S Compound Name
Hydrogen Sulfide Structure
Hydrogen Sulfide Thermochemistry
Hydrogen Sulfide Hazards
Hydrogen sulfide is somewhat denser than air; a combination of H2S and air can be explosive.
The explosive properties of Hydrogen Sulfur (or if we write the chemical formula of hydrogen sulphide, it is H2S) are as follows:
Hydrogen Sulfide Properties
Hydrogen sulfide combines with oxygen and gives off a blue fire to frame sulfur dioxide (SO2) and water. As a rule, hydrogen sulfide goes about as a diminishing specialist, particularly within the sight of base, which structures SH−.
At high temperatures or within the sight of impetuses, sulfur dioxide reacts with hydrogen sulfide to frame natural sulfur and water. This response is misused in the Claus interaction, a significant mechanical strategy to discard hydrogen sulfide.
Hydrogen sulfide is marginally solvent in water and goes about as a frail corrosive (pKa = 6.9 in 0.01 = 0.1 mol/litre arrangements at 18 °C), giving the hydrosulfide particle HS−.
(likewise composed SH−).
Hydrogen sulfide and its solutions are colourless. When presented to air, it gradually oxidizes to frame natural sulfur, which isn't dissolvable in water. The sulfide anion S2− isn't found in an aqueous solution.
Hydrogen Sulfide Geometry
Hydrogen sulfide goes about as a reducing specialist. H2S Lewis structure is a combination of hydrogens and one sulfur atom. Sulfur is the focal particle and contains 2 solitary sets though both hydrogens are associated with the focal molecule with the assistance of a single bond.
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Hydrogen Sulfide Preparation
Hydrogen sulfide is most regularly acquired by its detachment from acrid gas, which is petroleum gas with a high substance of H
2S. It can likewise be delivered by treating hydrogen with liquid natural sulfur at around 450 °C. Hydrocarbons can fill in as a wellspring of hydrogen in this process.
Sulfate-lessening (resp. sulfur-decreasing) microorganisms produce usable energy under low-oxygen conditions by utilizing sulfates (resp. basic sulfur) to oxidize natural mixtures or hydrogen; this produces hydrogen sulfide as a side-effect.
We can produce hydrogen sulfide by treating ferrous sulfide with a strong acid like HCl in standard lab preparation. A standard lab arrangement is to treat ferrous sulfide with a solid corrosive in a Kipp generator:
FeS + 2 HCl → FeCl2 (l) + H2S (g)
Most metals and non-metals sulfides after exposure to H2O liberate Hydrogen sulfide. For use in subjective inorganic investigation, thioacetamide is utilized to create H2S, the reaction is as follows:
CH3C(S) N H2 + H2O (l) → H2S + CH3C(O)NH2
Thioacetamide Water Hydrogen sulfide Acetamide
Many metal and nonmetal sulfides, for example, aluminium sulfide, phosphorus pentasulfide, silicon disulfide free hydrogen sulfide upon openness to water:
6 H2O + Al2S3 → 3 H2S + 2 Al(OH)3
This gas is likewise delivered by warming sulfur with strong natural mixtures and by diminishing sulfurated natural mixtures with hydrogen.
Water warmers can help the transformation of sulfate in water to hydrogen sulfide gas. This is expected to giving a warm climate reasonable to sulfur microscopic organisms and keeping up the response that connects sulfate in the water and the water warmer anode, which is generally produced using magnesium metal.
Hydrogen Sulfide Uses
The fundamental utilization of hydrogen sulfide is a forerunner to basic sulfur. A few organosulfur compounds are delivered utilizing hydrogen sulfide. These incorporate methanethiol, ethanethiol, and thioglycolic acid.
After joining with soluble base metal bases, hydrogen sulfide converts to salt hydrosulfides, for example, sodium hydrosulfide and sodium sulfide:
H2S + NaOH → NaSH + H2O
Sodium Hydroxide Sodium Hydrosulfide
On the further reaction of NaSH with NaOH, we get the following compound:
NaSH + NaOH → Na2S + H2O
Sodium Sulfide
Fact: These mixtures are utilized in the paper-making industry. In particular, salts of SH− break connections among lignin and cellulose segments of mash in the Kraft process.
Reversibly sodium sulfide within the sight of acids transforms into hydrosulfides and hydrogen sulfide; this provisions hydrosulfides in natural arrangements and is used in the creation of thiophenol.
Hydrogen Sulfide Phase Diagram
Hydrogen sulfide is a gas at STP conditions. However, at low temperature and/or high pressures the gas turns to a liquid or a solid state.
The hydrogen sulfide phase diagram describes the detailed phase behaviour with changes in temperature and pressure.
The below graph between the critical point and the triple point shows the change in the boiling point of hydrogen sulfide point with changes in pressure. Also, it shows the saturation pressure with changes in temperature:
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Observations
At the critical point, no change in state occurs when its pressure is increased or if heat is added.
Here, the triple point of a substance (hydrogen sulfide) is the temperature and pressure at which the three phases viz: gas, liquid, and solid coexist in thermodynamic equilibrium.
Hydrogen Sulfide Applications
Hydrogen sulfide is utilized to isolate deuterium oxide, or hefty water, from ordinary water through the Girdler sulfide measure.
Researchers from the College of Exeter found that cell openness to limited quantities of hydrogen sulfide gas can forestall mitochondrial harm.
At the point when the cell is focused on illness, proteins are brought into the cell to deliver limited quantities of hydrogen sulfide. This examination could have further ramifications on forestalling strokes, coronary illness, and arthritis.
A suspended liveliness-like state has been prompted in rodents with the utilization of hydrogen sulfide, bringing about hypothermia with an attending decrease in metabolic rate. Oxygen request was likewise diminished, along these lines ensuring against hypoxia. Furthermore, hydrogen sulfide has been appeared to diminish irritation in different situations.
FAQs on Hydrogen Sulfide: Definition, Properties, and Preparation
1. What is hydrogen sulfide and what is its chemical formula?
Hydrogen sulfide is a chemical compound that is a colourless, flammable, and highly toxic gas. It is known for its characteristic pungent smell of rotten eggs. The chemical formula for hydrogen sulfide is H₂S, indicating that one molecule consists of two hydrogen atoms covalently bonded to a single sulfur atom.
2. What are the main physical and chemical properties of hydrogen sulfide?
Hydrogen sulfide (H₂S) has several distinct properties that are important in chemistry:
- Odour: It has a strong, unpleasant odour of rotten eggs, detectable even at very low concentrations.
- State: It is a gas at standard temperature and pressure.
- Acidity: H₂S is a weak diprotic acid when dissolved in water, forming hydrosulfuric acid.
- Reducing Agent: It is a powerful reducing agent because the sulfur atom is in its lowest oxidation state (-2) and can be easily oxidised.
- Solubility: It is slightly soluble in water.
3. Is hydrogen sulfide gas flammable?
Yes, hydrogen sulfide is a highly flammable gas. When mixed with air, it can form an explosive mixture. It burns in oxygen with a blue flame to produce sulfur dioxide (SO₂) and water (H₂O). The autoignition temperature is 260 °C (500 °F), so it can ignite without an open flame if it comes into contact with a hot surface.
4. What are the most common industrial uses of hydrogen sulfide?
Despite its toxicity, hydrogen sulfide has several important industrial applications. Its primary use is as a chemical intermediate in the production of elemental sulfur, sulfuric acid, and thiols (mercaptans). It is also used in metallurgy for preparing metallic sulfides and in the manufacturing of various specialty chemicals and pharmaceuticals.
5. How is hydrogen sulfide typically prepared in a laboratory?
In a standard laboratory setting, hydrogen sulfide gas is commonly prepared using a Kipp's apparatus. The reaction involves treating a metal sulfide, usually ferrous sulfide (FeS), with a dilute non-oxidising acid like hydrochloric acid (HCl) or sulfuric acid (H₂SO₄). The chemical equation for the reaction is: FeS(s) + 2HCl(aq) → FeCl₂(aq) + H₂S(g).
6. What determines the molecular geometry of hydrogen sulfide?
The molecular geometry of H₂S is determined by the VSEPR (Valence Shell Electron Pair Repulsion) theory. The central sulfur atom has two bonded pairs of electrons (with two hydrogen atoms) and two lone pairs of electrons. These four electron pairs give it a tetrahedral electron geometry. However, the two lone pairs repel the bonding pairs more strongly, compressing the H-S-H bond angle to approximately 92.1°. This results in a bent or V-shaped molecular geometry.
7. Why is hydrogen sulfide (H₂S) a gas at room temperature while water (H₂O) is a liquid?
This difference is due to the presence of strong hydrogen bonding in water. Oxygen is highly electronegative, creating significant partial charges on the O and H atoms in H₂O, which leads to strong intermolecular hydrogen bonds. Sulfur is much less electronegative than oxygen, so the S-H bonds in H₂S are less polar. As a result, hydrogen sulfide does not form strong hydrogen bonds, leading to weaker intermolecular forces and a much lower boiling point, making it a gas at room temperature.
8. What makes hydrogen sulfide gas so toxic to humans?
Hydrogen sulfide is highly toxic because it interferes with cellular respiration at the molecular level. It acts as a poison by inhibiting cytochrome c oxidase, a critical enzyme in the electron transport chain within mitochondria. By stopping this enzyme's function, H₂S prevents cells from using oxygen effectively, leading to cellular suffocation, especially in the central nervous system. At high concentrations, this can cause immediate loss of consciousness and death.
9. What is the role of H₂S in the qualitative analysis of metal ions?
In inorganic qualitative analysis, hydrogen sulfide is a crucial group reagent used to separate metal ions into different groups based on the solubility of their sulfides. By controlling the pH of the solution, the concentration of sulfide ions (S²⁻) can be adjusted. In an acidic medium (Group 2 analysis), only the metal ions with very low solubility products (like CuS, PbS) precipitate. In a basic medium (Group 4 analysis), metal ions with higher solubility products (like ZnS, NiS) will precipitate.
