Chloramine, also sometimes referred to as monochloramine, has the chemical formula NH2Cl. It is a pale yellow to colorless liquid and has a strong pungent smell.
It is highly unstable in concentrated form and decomposes violently above – 40 °C temperature. It is produced as a result of the reaction between ammonia and sodium hypochlorite, as per the following reaction:
NH3 + NaOCl —-> NH2Cl + NaOH
Chloramine is used for the disinfection of drinking water as well as swimming pools.
A few important properties of NH2Cl are:
|Chemical Name||Chloramine or Monochloramine|
|Molecular weight||51.476 g/mol|
|Boiling Point||Colorless to yellow|
|Melting Point||−66 °C|
Hey Friends!! We are here again with another interesting topic to widen your chemistry knowledge.
So, if want to know more about chloramine, stay with us till the end.
NH2Cl Lewis Structure
In 1916, Gilbert N. Lewis put forth a concept that described the chemical bonding inside a molecule through pictorial representation. These illustrations came to be known as Lewis diagrams.
Here, the atomic symbols are used to represent different atoms while the dots around these symbols represent the valence electrons of that atom, hence, these structures are also known as electron dot structures.
The electrons inside an atom revolve around the nucleus in definite circular paths, known as shells.
The shell located farthest from the nucleus is known as the valence shell and the electrons housed in this shell are known as valence electrons.
As per the octet rule, the atoms form bonds to become stable by gathering eight electrons in their valence shell. Therefore, only the valence electrons of an atom are allowed to participate in chemical bonding.
The exception to this rule is hydrogen that becomes stable with two valence electrons i.e. by acquiring the electronic configuration of its nearest noble gas, helium.
The Lewis structures depict the bond formation inside a molecule by displaying the bonding as well as non-bonding electrons of an atom.
The Lewis structure of NH2Cl is given below:
Drawing Lewis Structure of NH2Cl
We will now draw the Lewis structure of chloramines in step by step manner.
• First of all, we will calculate the total number of valence electrons in one molecule of NH2Cl. This is done by determining the valence electrons of each of the participating atoms and then adding them.
In the case of NH2Cl, the numbers of valence electrons in different atoms are as follows:
Nitrogen atom= 5 valence electrons
Hydrogen atoms = 1 X 2 = 2 valence electrons
Chlorine atom= 7 valence electrons
Therefore, total number of valence electrons in NH2Cl = 5 + 2 + 7 = 14
• Now, we will choose the central atom for the molecule. Usually, the least electronegative atom is chosen as the central atom.
For NH2Cl, we will take nitrogen as the central atom. All other atoms are assumed to be bonded with the central atom.
• In the next step, the central atom and the bonding groups are connected with the help of a single bond.
By doing so we can determine the number of valence electrons associated with each atom and also, the number of electrons required by each atom to complete their octet. The NH2Cl molecule appears as follows:
• As seen in the above diagram both the hydrogen atoms are satisfied after having two electrons in their valence shell.
Also, the nitrogen, as well as the chlorine, atoms have eight electrons in their valence shell. Therefore, all the atoms have a complete octet
• Hence, the Lewis structure of NH2Cl is as follows:
• However, to make sure that we have drawn the right structure we will calculate the formal charge of this structure.
• The formal charge is the hypothetical concept that helps us to evaluate the accuracy of a Lewis structure.
For the best possible Lewis structure of a molecule, the value of the formal charge should be close to zero or zero itself. This indicates the stability of the structure.
• The formal charge for a molecule is given by the following formula:
Formal Charge = [Total no. of valence e– in Free State] –
[Total no. of non-bonding e– – 1/2 (Total no. of bonding e–)]
• Now, we will calculate the formal charge for each of the individual atoms of the NH2Cl molecule:
For the Nitrogen atom, Formal charge =  –  – ½
= 5- 5 = 0
For the Hydrogen atom, Formal charge =  –  – ½
For the Chlorine atom, Formal charge =  –  – ½
As the formal charge on each of the individual atoms is 0. Therefore, the total formal charge on the NH2Cl molecule also becomes 0.
• Hence, the above-drawn structure is the correct Lewis structure for the NH2Cl molecule.
Molecular Geometry of NH2Cl
The arrangement of the atoms of a molecule around each other, in space, defines its molecular geometry.
It is a three-dimensional model of the molecule and represents the position of each atom of the molecule relative to each other, along with their bond angles and bond lengths.
The Valence Shell Electron Pair Repulsion (VSEPR) Theory was given by Ronald Gillespie and Ronald Nyholm. This theory helps in determining the molecular geometry of a molecule.
It states that the total number of bond pairs and lone pairs of electrons carried by the central atom of any molecule decide the shape of that molecule.
The VSEPR theory further states that as all the electrons are negatively charged, a certain degree of repulsion exists between the electron pairs present inside a molecule.
The degree of repulsion increases in the following order:
Bond Pair-Bond Pair < Bond Pair- Lone Pair < Lone Pair- Lone Pair
The theory further states that the shape or geometry of a molecule is determined by these inter-electronic repulsion forces.
The electron pairs inside the molecule would tend to arrange themselves as far as possible from other electron pairs, to avoid the inter-electronic repulsion, and stabilize the molecule by lowering the energy.
The Lewis structure of a molecule helps us determine the number of bond pairs and lone pairs of electrons present in a molecule, and hence, the geometry of the molecule.
In the case of NH2Cl, the central atom i.e. nitrogen has one lone pair and three bond pairs of electrons. To determine the geometry of this molecule we will refer to the AXN formula
In the AXN formula, A is the central atom, X is the bonded groups attached to the central atom while N symbolizes the number of lone pairs.
Therefore, in the NH2Cl molecule three groups viz. one chlorine atom and two hydrogen atoms are attached to the central atom i.e. nitrogen, which also carries a lone pair of electrons. Hence, the AX3N notation is assigned to this molecule.
Looking at the AXN notations in the chart given below:
Therefore, the molecular geometry for NH2Cl as per the AXN formula is Trigonal Pyramidal.
Hybridization of NH2Cl
Hybridization is the process of the intermingling of different orbital of similar energy to form a new orbital.
The names of these orbital include all the participating orbital. For example, sp2 orbital includes one s and two p orbital. Similarly, dsp3 includes one s, three p, and one d-orbital.
As per the VSEPR theory, the steric number is the sum of the total number of atoms bonded to the central atom and the lone pair of electrons on the central atom.
It is used to determine the hybridization of a molecule. The formula for steric number is given below:
Steric Number = Number of sigma (σ) bond on central atom + lone pair on the central atom
The hybridization of any molecule based on its steric number is determined using the following table:
|Steric number||Hybridization State|
Now, we can calculate the steric number for the NH2Cl molecule.
Steric number for the NH2Cl molecule =  +  = 4
Therefore, the hybridization of NH2Cl molecule based on its steric number is sp3.
• Also, we know that the hybridization state for the nitrogen atom is sp3 and it contains 5 electrons in its valence shell. Therefore, in the ground state it can be written as:
• In the case of NH2Cl, the three electrons from the bonding groups accommodate themselves in the half-filled 2p orbital.
• Therefore, after accommodating the three electrons shared with the bonded groups and completing its octet. The hybridization state of NH2Cl is sp3.
Polarity of NH2Cl
The polarity of a molecule depends upon the electronegativity of different molecules present in a molecule.
The higher electronegativity difference indicates a polar molecule. Moreover, the geometry of the molecule also plays a vital role in determining the polarity.
For example, in the case of a linear molecule, the positive and negative charges may cancel each other making it non-polar.
In the case of NH2Cl, the shape is trigonal pyramidal i.e. asymmetric and also, chlorine is more electronegative than the nitrogen atom. Due to this, a slight positive charge appears on the nitrogen atom, while a slight negative charge develops on the chlorine atom.
Hence, due to the unequal charge distribution and asymmetrical shape of the molecule, the NH2Cl molecule is polar.
Related articles you must read
The Lewis structure of NH2Cl is given as:
The molecular geometry of NH2Cl is trigonal pyramidal.
The hybridization of NH2Cl is sp3.
NH2Cl is a polar molecule.