What is a sulphur allergy

What is a sulphur allergy

Sulphur does not react with dilute non-oxidizing acids.

Reaction of sulfur with bases

Sulphur reacts with boiling aqueous potassium hydroxide, KOH, to form sulphide and thiosulphate species.

S8(s) + 6KOH(aq) → 2K2S3 + K2S2O3 + 3H2O(l)

Sulphur Dioxide and Hydrogen Sulfide Reaction | SO2 + H2S = S + H2O Balanced Equation

Sulphur dioxide and hydrogen sulfide are gases and they react with each other in the presence of moisture to give sulphur and water as products.

This reaction is a sulphur forming reaction and also a redox reaction.

Redox reaction

A reaction, which undergo oxidation and reduction in same time is defined as a redox reaction.

Reaction of sulfur with the halogens

Sulphur racts with every the halogens upon heating.

Sulphur reacts with fluorine, F2, and burns to form the hexafluoride sulphur(VI) fluoride.

S8(s) + 24F2(g) → 8SF6(l) [orange]

Molten sulphur reacts with molten sulphur to form disulphur dichloride, S2Cl2.

This apparently smells dreadfully. With excess chlorine and in the presence of a catalyst, such as FeCl3, Snl4, etc., it is possible to make a mixture containing an equilibrium mixture of red sulphur(II) chloride, SCl2, and disulphur dichloride, S2Cl2

S8 + 4Cl2 → 4S2Cl2(l) [orange]

S2Cl2(l) + Cl2 ⇌ 2SCl2(l) [dark red]

Redox reaction between hydrogen sulfide and sulphur dioxide — balanced reaction

One sulphur dioxide molecule reacts with two hydrogen sulphide molecules and produces three sulfur atoms and two water molecules.

How do you identify H2S and SO2?

Both are colourless gases.

What is a sulphur allergy

Send to gases separately to two barium chloride solution.

  1. In one solution, a white precipitate forms. It is BaSO3.
  2. In other solution, there is no precipitate forming.

sulfur dioxide equation

Dioxide means an oxide with two oxygen atoms. Therefore chemical equation of sulfur dioxide is SO2.

What is the oxidation number of sulfur in h2s

First identify which atom has the higher electronegativity. Sulfur and hydrogen’s electronegativity values are 2.5 and 2.1 respectively.

So hydrogen should own positive oxidation number and sulfur has a negative oxidation number.

We know hydrogen’s only positive oxidation number is +1.

Using the oxidation number determing equation

Oxidation number of sulfur in H2S is -2.

SO2 properties

  1. Acidic
  2. Toxic
  3. Colourless
  4. Heavier than air

How do you discover SO2 and H2S in large scale?

In petroleum refining, H2S gas forms due to removing or decreasing sulfur in fuels.

Some refineries (old ones) burn H2S before releasing to the environment. When H2S burning in the O2 SO2 forms.

Will H2S + SO2 reaction will assist to reduce hydrogen sulfide environmental effects?

If H2S is produced or released from a plant in grand quantity, this reaction is a excellent way to recover H2S. But this depend availability of sulfur dioxide gas.

What is a sulphur allergy

Is HS + SO2 a redox reaction?

Yes. H2S is oxidized to sulfur and SO2 is reduced to sulfur.

oxidation of hydrogen sulfide to sulfur dioxide

When hydrogen sulfide is heated with oxygen gas, sulfur dioxide is given as the product. Here sulfur dioxide is oxidized to sulfur dioxide.

H2S properties

  1. Very toxic
  2. Weak Acidic
  3. Colurless
  4. Heavier than air


SO2 and H2S are extremely toxic gases and causes harmful injuries to humans, animals and whole environment.

Inhaling H2S in extremely little amounts is enough to cause death. H2S toxic levels are mentioned below.

Hydrogen sulfide toxicity levels

This toxicity levels of H2S and effects were taken by Safety and Health Topics / Hydrogen Sulfide at https://www.osha.gov . Concentrations are expressed in ppm values. In this experiment, your should be extremely careful to get protected from these hazardous chemicals.


what is sulphur + H2O?

Sulfur does not react with water and also does not dissolve in water.

water + hydrogen sulfide reaction

When hydrogen sulfide dissolve in water, a feeble acidic solution is given.

Related Topics to SO2 and H2S

Oxidation number of S and H in H2SSulfur dioxide preparing and reactionsredox reaction (oxidation — reduction)Safety and Health Topics / Hydrogen Sulfide Nickel +2 ion and ammonia solution reaction Alkali ground metal reactionsOxidation Numbers of Elements in Periodic Table Alkali metals reactions Identify cations by precipitating Precipitates compounds colours Ammonia preparing reactions

Updated October 2017.

The quantities originally recomended for this demonstration mean it is prohibited under the 2014 explosives regulations. We own removed the kit list and instructions from this article.

There are several ways to protest to students the differences between elements, mixtures and compounds. The difficulty in separating the elements in a compound is generally shown by using the physical and chemical properties of iron and sulfur. However, when teaching this topic I prefer to use a demonstration based on the reaction between zinc and sulfur.

This reaction offers the same teaching opportunities as the Fe/S reaction but uses diverse techniques for identifying the nature of the reactants and products. Electrical conductivity can be used to show the differences between the elements, rather than magnetism, and a mixture of the reactants can be separated by reaction with water or dilute acid (if zinc dust is used). This provides a more detailed analysis of the chemistry involved in the reaction.

The products of this reaction bear little resemblance to the starting elements, pale blue zinc and bright yellow sulfur. Students can see that a new compound has been formed. The pale yellow residue is a mixture of zinc oxide and zinc sulfide.

Reducing this residue (by electrical or chemical means) back to zinc demonstrates the chemical differences between mixtures and compounds. A drop of hydrochloric acid on the residue can be a fitting conclusion to the reaction, if done in a fume cupboard.

What is a sulphur allergy

The reaction produces the pungent, foul-smelling gas hydrogen sulfide which students often associate with stink bombs – once smelled never forgotten. Lead ethanoate paper turns black in the presence of the gas.

The reaction between zinc and sulfur

In this demonstration an intimate mixture of zinc and sulfur produces an unusual chemical reaction when heated.

What is a sulphur allergy

A brilliant flash of light, followed by boiling sparks, a hissing sound and a mushroom-shaped cloud of white smoke are generated.

Teaching goals

Zinc is an essential element – the mineral is required for skin and bone growth, and our bodies use zinc to process food and nutrients. Zinc ions are vital components in several diverse enzymes found in the body. A pale yellow, odourless, brittle solid, sulfur is essential to life too, occurring in the amino acids cysteine and methionine and therefore in numerous proteins.

What is a sulphur allergy

It is a minor constituent of fats, body fluids, and skeletal minerals.

The chemical reactions which are occurring in the reaction are:

Zn(s) + S(s) → ZnS(s) ΔHf = –206.0 kJ mol-1

Zn(s) + ½O2(g) → ZnO(s) ΔHf = –348.3 kJ mol-1

S(s) + O2(g) → SO2(g) ΔHf = –297.0 kJ mol-1

The overall reaction needs heat to get started but the heat it produces is enough to sustain the reaction thereafter.

Zinc can be obtained by electrolysis of zinc sulfate or by smelting in a process similar to the production of iron from the blast furnace.

First the zinc ore is roasted in air, converting it to zinc oxide:

2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g)

Coke and the roasted ore are fed into the top of the furnace with air blasted in at the bottom. The most significant reaction taking put is:

ZnO(s) + CO(g) → Zn(g) + CO2(g)

Unlike the production of iron (mp = 1535°C; bp = 2750°C), zinc (mp = 420°C; bp = 907°C) is produced as a vapour. Cooling the zinc vapour to produce a liquid results in the re-oxidation of the metal. This problem was solved in the 1950s by Imperial Smelting of Bristol.

The zinc vapour is sprayed with molten lead.

What is a sulphur allergy

This chills and dissolves the zinc so rapidly that re-oxidation is minimal. Molten lead and zinc are only partially miscible in each other and so, by cooling the solution, zinc separates as a liquid of almost 99% purity. Vacuum distillation can further refine the liquid to 99.99% purity. This method has the advantage that the charge composition is not critical and mixed Zn/Pb sulfide ores (often found together) will produce both metals simultaneously, the lead being tapped from the bottom of the furnace.

When using this demonstration, it is worth mentioning that zinc is applied in thin layers to iron and steel products to stop them rusting.

This process is called galvanising. More than half of the zinc consumed each year is used for galvanising. About 7.7 kg of zinc is used to protect the average car from rust.

Reaction of sulfur with air

Sulphur burns in air to form the gaseous dioxide sulphur(IV) oxide, SO2.

S8(s) + 8O2(g) → 8SO2(g)

SO2 + H2S = S + H2O reaction

This is a redox reaction (oxidation — reduction). Sulphur atom in the sulphur dioxide molecule is reduced to sulfur while sulphur atom in the hydrogen sulphide is oxidized to sulfur.

This reaction occurs in the presence of moisture. SO2 and H2S are in gaseous state and produced sulfur is given as a pale yellow solid.

  1. SO2 is reduced to sulfur.
  2. H2S is oxidized to sulfur.

Balancing the equation

Due to forming sulfur by both H2S and SO2, we follow a special method to balance this equation. Remember how to balance a redox reaction and its steps!

  1. At initial situation, there are two sulfur atoms in the left side of the equation.

    But correct side has only one. So add one more sulfur atom to the correct side.

  2. Then take the oxidation number difference in oxidation and reduction. Oxidation number differences of oxidation and reduction are 2 and 4 respectively. Next exchange the differences.

    What is a sulphur allergy

    See the figure how exchanging is done.

  3. Find the oxidation numbers of each atom to discover which atoms are oxidized and reduced. When finding the oxidation numbers, we see SO2 is reduced and H2S is oxidized.
  4. Finally balance the H2O by checking oxygen atoms of left and correct sides.

Reaction of sulfur with water

Sulphur does not react with water under normal conditions.