H2S Polar Or Nonpolar| Easy Explanation

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Hydrogen sulfide (H2S) is a colorless gas with a pungent “rotten egg” odor at low concentrations.
H2S is a slightly polar molecule because of the small difference in electronegativity values of Hydrogen (2.2) and Sulfur (2.58) atoms.
In addition, the presence of two lone pairs that are on the opposite side of the two Hydrogen atoms also makes the molecule more polar and causes a bent shape geometrical structure of H₂S.

Name of molecule	Hydrogen sulfide
Structure	Bent shape
No of lone pairs	Two
Valence electrons	Eight
Molar mass	34.1 g/mol
Hydrogen sulfide (Hydrosulfuric acid) formula	H2S

Polarity of H2S

To understand the partial slightly polar nature of H₂S, we need to understand its structure.
The molecule has two H atoms and a single S atom.
Each H atom has only one electron which is also its valence electron.
Hence there are two valence electrons for the H atom ( as there are two H atoms).
Sulfur has six valence electrons. The table below gives details about the electronic configuration of constituent atoms and their valence electrons.

Atom	Electronic Configuration	Valence Electrons (VEs)
1H	1s1	1
16S	1s22s22p63s23p4.	6

VEs in Hydrogen sulfide = VEs in 1 S atom + VEs in 2 H atoms
VEs= 1(6)+2(1) =8

The hybridization of the Hydrogen sulfide molecule is sp3.
The Sulfur atom is in the center bonding with two H atoms forming the bond angle less than 180 degrees.
According to the VSEPR theory, the lone pairs of electrons repel each other.
There are two lone pairs of the sulfur atom in the Hydrogen sulfide lewis structure.
Also, sulfur is bonded to two H atoms.
The repulsion between the 2 lone pairs of electrons plays a major role in making its bent molecular geometry.

Properties of Hydrogen sulfide

• Hydrogen sulfide is a colorless toxic gas.
• It emanates from sewers and as a by-product of industrial processes
• In low concentrations, it smells like rotten eggs.
• Soluble in water and many other liquids. It forms hydro-sulfuric acid when dissolved in water.
• It is highly explosive and only requires a concentration of 4% for a flash fire when exposed to a relatively cool heat source of 232 Degree Celsius.
• It is heavier and 1.136 times denser than air. This means it is likely to be found in low-lying areas with little to no ventilation.
• Its boiling point is -60.4 degrees Celsius.
• Is H₂S Polar or Nonpolar: H₂S is slightly polar

H2S Lewis Structure

In the H2S Lewis structure, there are two hydrogen atoms on both sides of the central sulfur atom.
There are eight valence electrons in the molecule.
The sulfur atom is in the middle of the structure and valence electrons are arranged around it.
Two hydrogen atoms are located on both sides of the central sulfur atom.
Sulfur shares electrons with both the neighboring hydrogen atoms to make the molecule stable.
Two out of six valence electrons participate in bond formation.
The remaining four electrons are unbonded electrons and are displayed as dots near the sulfur atom.
These lone pairs of electrons make the H2S structure bent.

What is Polarity?

The distribution of electrical charge over the atoms joined by the bond causes polarity.
Specifically, it is found that bonds between atoms of different elements are electrically inequivalent. In hydrogen chloride, for instance, the H atom is slightly positively charged whereas the Cl atom is slightly negatively charged. (For details check the full article “Is HCl polar or nonpolar?”.
The slight electrical charges on dissimilar atoms are called partial charges, and the presence of partial charges signifies the occurrence of a polar bond.

Examples of Polar molecules

Some examples of polar molecules are Water (H₂O), Ethanol, Ammonia, and SO2 (Sulfur Dioxide).

Polarity of Hydrogen Sulfide

The molecular geometry of Hydrogen sulfide is polar but the bonds are not polar.
Polarity is determined by electronegativity. A molecule is polar if the structure of that molecule is not symmetric.
In the case of symmetric structure, the dipole vectors on each molecule cancel each other, resulting in the nonpolar nature of the molecule.

Polarity of Water Molecules

H₂O is another example of a polar molecule.
The molecule consists of two H atoms and one oxygen atom.
The difference in electronegativity is 1.2 for each of the H-O bonds.
Since oxygen is the more electronegative atom, it exerts a greater pull on the shared electrons.
Oxygen also has two lone pairs of electrons. This develops a dipole moment in the water molecules.

Polarity of CO₂

Carbon dioxide is a nonpolar molecule that contains polar bonds.
CO₂ is a linear molecule and the C=O are polar bonds.
The central carbon contains a net positive charge while the two outer oxygens a net negative charge.
However, since the carbon dioxide molecule is linear, these two bond dipoles cancel each other out.
As a result, the overall molecule has no dipole.

CO2 lewis structure shows CO2 has two oxygen atoms and one carbon atom bonded together with a covalent bond. Two Oxygen atoms are located on the sides of the carbon atom where both these atoms share electrons and form bonds The carbon atom is in the central position as it is the least electronegative atom in the molecule.

Polarity of Ammonia (NH₃)

The polarity of the NH3 molecule is due to the electronegativity difference between N (3.04) and H ((2.2).
This electronegativity difference causes three dipole moments in one direction.
This results in a net dipole moment that makes ammonia a polar molecule.
In addition, the NH3 lewis structure shows that there is a lone pair of electrons present on Nitrogen.
This exerts an outward force on the bond due to which the shape of NH3 becomes unsymmetrical.

Uses of H₂S

• Precursor for elemental Sulfur.
• It plays a vital role in signaling pathways in the human body. 
• Hydrogen sulfide is used primarily to produce sulfuric acid and sulfur.
• Farmers use H₂S as an agricultural disinfectant and it is found in some cutting oils, which are coolants and lubricants designed specifically for metalworking and machining processes, and other lubricants.

Molar Mass of H₂S

Molar mass of S =32.066 g/mol.
Hydrogen molar mass = 1.00794 g/mol.
Molar mass of H₂S = 34.1 g/mol

Hydrogen Sulfide Toxicity

1. Hydrogen sulfide is a highly toxic gas and is the biggest cause of inhalational deaths.
2. Low-level exposures to H₂S may produce local eye and mucous membrane irritation.
3. High-level exposures may produce fatal systemic toxicity
4. Exposures of 700-800 ppm of Hydrogen sulfide can cause loss of consciousness.

Dipole moment

When two atoms with different electronegative values interact, the electrons tend to come closer to the more electronegative atom. This movement of electrons is represented via the bond dipole moment.
It is the product of the charge and the distance between the centers of the positive and negative charges.
It is denoted by the Greek letter ‘µ’.

Dipole Moment (µ) = Charge (Q) * distance of separation (r)

It is measured in Debye units denoted by ‘D’.
1 D = 3.33564 × 10^-30 C.m, where C is Coulomb and m denotes a meter.

Geometrical Structure of H₂S

The presence of two lone pairs of electrons makes the molecule bend.
Since sulfur is more electronegative than hydrogen, this makes the molecule slightly polar.
The vectorial sum of the bond dipole moments in H2S produces a non-zero total dipole moment.
As a result, Hydrogen sulfide shows dipole-dipole interactions.

Summary

Some of the summary points are listed below:

• Hydrogen sulfide is slightly polar because of the presence of lone pair of electrons in Sulfur and the electronegativity difference between Sulfur and H atoms.
• There are eight valence electrons present in the molecule of hydrogen sulfide.
• Hydrogen sulfide molecule has an angular geometry with a non-zero dipole moment.
• H2S is a highly toxic gas and can be very dangerous if inhaled.

Related Links

HCN Lewis Structure| Step By Step Construction

N₂O Lewis Structure| Laughing Gas

SiO2 Lewis Structure

CO Lewis Structure & Molecular Geometry

Is HCl Polar or Nonpolar? – What’s Insight

SO2 Lewis Structure| 4 Simple Steps – What’s Insight

SO2 Polar or Nonpolar

Frequently Asked Questions

Some of the frequent questions are given below. If you have any questions please feel free to post a comment.

1. What is h2s acid’s name?

H2S (hydrogen sulfide) is a colorless, very deadly gas with a foul stench similar to rotten eggs. It is soluble in carbon disulfide and mildly soluble in water. When it dissolves in water, it generates a very weak dibasic acid known as hydro sulfuric acid.
Check the full article “Hydrogen sulfide acid”.

2. Is h2s ionic or covalent?

Because hydrogen has an electronegativity of around 2.2 and sulfur has an electronegativity of 2.56, H2S bonds are covalent. Hydrogen is a reducer and sulfur oxidizer due to its lower electronegativity.

3. What are the effects of the presence of hydrogen sulfide in water?

The presence of hydrogen sulfide in water may cause headaches, dizziness, nausea, coma, blurred vision, hemorrhage

4. What is the Polar covalent bond?

A polar covalent bond is a kind of covalent bond that lies between pure covalent bonds and ionic bonds. Such bonds are formed when the difference in electronegativity between the anion and the cation is between 0.4 and 1.7, they form.

5. Is BF3 Polar or Nonpolar?

BF3 is a non-polar compound. In BF3, the central boron atom has sp2 hybridized orbitals, resulting in an unfilled p orbital on the Bron atom and trigonal planar molecular geometry. Because the Boron-Fluorine bonds are all 120 degrees apart, any net dipole in that plane is canceled out. Even if each B-F bond is polar, the net dipole moment is zero because adding the bond vectors cancels everything out. Check the full article “Is BF3 polar or nonpolar?”.

6. Is MgCl2 Ionic or Covalent?

When the magnesium atom loses two electrons to create the Mg²⁺ ion and each chlorine receives one electron to form the Cl^– ion, an ionic connection is formed between the magnesium and chlorine atoms.
Check “Is MgCl2 ionic or covalent?”.

7. Is SiCl4 polar or nonpolar?

SiCl4 (silicon tetrachloride) is a nonpolar molecule. Because the four chemical bonds between silicon and chlorine are uniformly distributed, SiCl4 is non-polar. A polar covalent bond is a type of covalent link that is intermediate between pure covalent bonds and ionic bonds. When the difference in electronegativity between the anion and the cation is between 0.4 and 1.7, such bonds occur.
Check the full article “Is SiCl4 polar or nonpolar?”.

The bonds of H₂S are covalent because H has an electronegativity of about 2.2, and sulfur 2.56. Two H atoms form a covalent bond with the central Sulfur atom. These bonds take up four valence electrons out of eight, and hence there are four remaining valence electrons left. This arrangement leads to the sp3 hybridization of the molecule. 

Polarity is the distribution of electrical charges over the atoms in a molecule.
For instance, In hydrogen chloride, the H atom is slightly positively charged whereas the chlorine atom is slightly negatively charged. The presence of partial charges signifies the occurrence of a polar bond.

H₂O higher dipole moment than Hydrogen sulfide because of the fact that oxygen is more electronegative than sulfur due to which oxygen pulls the electron more than s/ulfur.

Strong electrostatic forces of attraction between the positively charged nucleus and shared pair of valence electrons are present. Both sulfide and hydrogen are nonmetals. Covalent bond forms between nonmetals.

H2S exhibits dipole-dipole intermolecular forces.
sulfur is more electronegative than hydrogen and makes the molecule slightly polar and bent shaped.
The bent shape of the molecule makes the vectorial sum of the bond dipole moments will produce a non-zero.

Conclusion

This article answers the question “Is H₂S polar or nonpolar”.
We hope after reading the article, you are able to understand the polar nature of H₂S and the molecular structure of H₂S. If you have any questions regarding this topic, feel free to post a comment.

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