Hypochlorite being a conjugate base of hypochlorous acid, readily reacts with different elements as it is an unstable chlorine oxoanion, monovalent inorganic anion, and chlorine oxide. Most of the hypochlorite salts exist as an aqueous solution as they cannot remain stable in other states of matter. Hypochlorite (ClO) is toxic for human beings because it is a strong irritant to the olfactory system and affects the mucous membrane to reduce the perception of a smell. Hypochlorite is known to active neutrophil granulocytes within humans as an innate defense mechanism that engulfs foreign particles that is hypochlorite in this case.
Stability of Hypochlorite
Being an anion, hypochlorite is known to be highly unstable and is available in liquid form when reacts with any cation. Here, it is important to understand that hypochlorite of lithium, calcium, and barium exists in an anhydrous condition. For industrial production, hypochlorite salts are produced by reacting chlorine with alkali and alkaline earth metal hydroxides. This reaction is always undertaken at room temperature to prevent the formation of chlorates. The reactions are: Cl2 + 2 NaOH → NaCl + NaClO + H2O 2 Cl2 + 2 Ca(OH)2 → CaCl2 + Ca(ClO)2 + 2 H2O Let us understand this compound in more detail by studying its lewis structure, geometry, hybridization, and polarity.
Lewis Structure of Hypochlorite (ClO)
A Lewis diagram is a structural representation of valence electron distribution around an atom. Moreover, it also explains the reason behind the formation of bonds and their behavior for newer properties. It is considered the foremost step if anyone wants to study a chemical compound.
Steps to Draw a Lewis structure of Hypochlorite (ClO)
Step 1: Determine the total number of valence electrons in one hypochlorite molecule. The chlorine atom has seven valence electrons, and the oxygen atom has six valence electrons. In addition to this, there is one more valence electron at hypochlorite available as a negative sign. Hence the total is 14. Step 2: Determine the number of valence electrons further required to complete the octet in one hypochlorite molecule. It is two as both chlorine and oxygen need eight valence electrons to complete their octet. Hence, the total number of valence electrons required by one hypochlorite molecule is 16. Step 3: Determine the central atom. Hypochlorite being a diatomic molecule does not require to have a central atom. Here, it is important to determine the atom that will make the maximum number of bonds. It can be analyzed by figuring out the electronegativity values of the participating atoms. The lower the electronegativity value, the more will be the number of bonds. In hypochlorite, it is chlorine that will make the maximum number of bonds. Step 4: Draw the skeleton. Write the symbols of both chlorine and oxygen placed adjacent to one another and place available valence electrons in pairs around them.
How formal charge is distributed on a hypochlorite molecule?
The formula of formal charge distribution is: Formal charge = Valence electrons – Unbonded electrons – ½ Bonded electrons For, Chlorine = 7 – 6 – 2/2 = 0 Oxygen = 6 – 6 – 2/2 = -1 As the total formal charge distribution on the hypochlorite molecule is -1, the aforementioned Lewis structure withholds most stability and credibility.
What type of bonds are formed in hypochlorite (ClO)?
From the Lewis structure, it is clear that only a single bond is forming between chlorine and oxygen atoms. It is due to the fact that both the atoms require only one valence electron to complete their octet. Single bonds are considered the strongest ones as they are purely made of sigma (σ) bonds. A strong overlapping of the orbitals takes place along the bonding axis of the hybrid orbitals that leads to the formation of a single bond in hypochlorite.
Molecular Geometry of Hypochlorite (ClO)
Hypochlorite is a diatomic molecule having a single bond, forming between the chlorine and oxygen atoms. This is the reason behind hypochlorite having linear geometry. It can be studied in the detail with the help of the Valence Shell Electron Pair Repulsion (VSEPR) Theory. According to it, both the atoms have an equal number of unbonded valence electrons present at an equal distance from one another. Due to this, they exert an equal force of repulsion in the opposite direction giving a linear structure to the hypochlorite molecule. In addition to this, the negative charge on hypochlorite molecule equally affects both chlorine and oxygen atoms till unbonded. As soon as hypochlorite bonds with a cation, hypochlorite bends to change its structure from linear to others depending upon the number of cations. Hence, hypochlorite has a primary linear structure that is readily available to bond and achieves a stable state. Molecular geometry is the three-dimensional pictorial representation of atoms within a molecule. It helps with determining the position of an atom and its behavior during the formation of a bond. Molecular geometry helps with studying bond length, bond angles, and other geometric parameters to predict the behavior of an atom within a bond formation.
Hybridization in Hypochlorite (ClO)
There are various generic formulas for hybridization such as AX, AX2, AXN, AX3, AX2N, AXN2, AX4, AX3N, AX2N2, AXN3, and AX3N2. Out of these, hypochlorite falls under AXN3 as it has one bonded pair of valence electrons, three lone pairs of valence electrons, linear molecular geometry, and tetrahedral electron geometry. Hence, the hybridization of chlorine in hypochlorite is sp3. The electronegativity of chlorine is lesser than oxygen. For chlorine in hypochlorite molecule, mixing and intermixing of one 2s-orbital and three 2p-orbitals takes place that forms four new hybrid orbitals having similar characteristics and energy levels. Hybridization is a mathematical and pictorial representation of bond formation taking place within a molecule. It shows the mixing and intermixing of various orbitals that give birth to new orbitals of similar energy. It is studied in the detail with the help of Valence Bond Theory (VBT). Hybridization determines energies, shapes, angles, and other components of the atomic orbitals.
Polarity in Hypochlorite (ClO)
Hypochlorite is a polar molecule and it has been confirmed from the Lewis Structure itself. It is clear from the formal charge distribution that the net dipole moment on one hypochlorite molecule is not zero. Due to the presence of a -1 charge, the hypochlorite molecule becomes an anion. The polar nature of hypochlorite cannot be confirmed by studying the electronegativity values of all the participating atoms. The electronegativity value of chlorine is 3.16 and that of oxygen is 3.44. By ideal condition, the difference in the electronegativity values of all the participating atoms must be greater than 0.4 to become polar. This rule is not applicable to hypochlorite as the electronegativity difference is less than 0.4. This anomaly is due to the presence of a -1 formal charge on the hypochlorite molecule that deviates it from fulfilling each property. Polarity is a property by which a molecule starts behaving like a magnet as two separate ends of anion and cations are formed within itself. But in the case of hypochlorite, it is an anion that looks for cation to complete its octet and achieve a stable condition. It is not essential for each molecule to fulfill each and every condition of being either a polar or nonpolar molecule. With this, let’s study about different uses of hypochlorite.
Uses of Hypochlorite
- It is used as a bleaching agent and disinfectant.
- It is used for various water treatment processes.
- It is a strong reagent for different chemical oxidation and chlorination reactions.
- It is used as an explosive or to initiate the combustion of organic materials.
- It is used as a deodorizer.
- It is used to remove stains.
- It is used to lighten hair color.
- It is used to oxidize primary alcohols into much stronger carboxylic acids.
To sum it up!
Hypochlorite is an exception of being a highly unstable compound showing all the true properties of covalent molecules. The Lewis structure clearly explains the formal charge distribution and presence of a dipole cloud on the molecule which makes it more available for the cations. Moreover, from the Lewis structure, it is clear that the chlorine atom has tetrahedral electron geometry by which it has sp3 hybridization. Moreover, the presence of an equal number of valence electrons on both chlorine and oxygen atoms further gives hypochlorite a linear structure.
