Hono Lewis Structure, Characteristics:19 Facts You Should Know

Hono is weak acid as well as monoprotic with the molecular weight of 47g/mol. Let us discuss about the more aspects of hono lewis structure in the below.

Nitrous acid or Hono is an oxoacid of nitrogen comprised of two oxygen atoms along with one hydrogen atom. It usually exists in solution as nitrite salts (NO2) with a prominent pungent smell and gives the appearance of a pale blue solution.

Let’s discuss the type of hybridization, molecular geometry, lewis structure and formal charge calculations associated with the hono lewis structure.

How to draw Hono lewis structure

Hono lewis structure contains three types of atoms Let’s draw the hono lewis structure by following below steps:


The hono lewis structure is associated with 18 valence electrons in its outermost shell. Nitrogen contributes 5 electrons and 12 by two oxygen atoms whereas the hydrogen atom has the participation of only 1 electron.


The electronegativity factor is a deciding factor as less electronegative atom will occupy the central position, hence N is placed at the center and O atoms place at the outer sides.


In hono, valence electrons (18 in total) will be placed in such a way that each of the participating atom’s octet gets full filled and eventually, they got a total of 8 electrons in their respective outmost shell.


Hono lewis structure resonance

Resonance corresponds to the movement of the electrons from one atom to another. Let’s discuss how it happened in hono lewis structure.

The lone pairs present on the oxygen atom can capable of participating in the resonance for Hono lewis structure and results in three different structure.

Out of all structures, I and III  are identical and contribute more significantly to the stability of the system as they do not carry any charges associated with them while the II structure is unstable comparatively.

Hono lewis structure resonance

Hono lewis structure shape

Every molecule has its structure depending upon the type of bonding with its neighboring atoms. Let’s look for the shape of the hono lewis structure.

The shape of the hono lewis structure is bent.  According to the AXN method, hono also comes under  AX2N type molecule which corresponds to the bent shape type of molecular shape where n occupies the central position while oxygen and hydrogen are present at the periphery as shown in the above figure.

Hono lewis structure shape

The AXN method is used to determine the shape of the hono lewis structure in which A= central atom, X = no of atoms directly attached to the nitrogen, N = no of lone pair on the central atom.

Hono lewis structure formal charge

Formal charges refer to the total charge carried by the intended structure. Let’s find the formal charge for the hono lewis structure.

 The formal charge for hono is zero and is calculated using the formula; (F= valence electrons-    unbonded electrons and -1/2 bonded electrons). Hono contains 18 valence electrons, 10 unbonded electrons and 10 bonded electrons.

Calculation of formal charge for the Nitrogen atom

  • Valence electrons = 5 ( as belonging to the second group)
  • Unbonded electron count = 2
  • Bonded electrons = 6
  • F.C =  5 – 2 –  6/2 =  0
  • Calculation of formal charge for oxygen atom
  • Total valence count = 6
  • Unbonded electron count = 4
  • Bonded electrons = 4
  • F.C = 6 -4 – 4/2 =  0
  • Hence total formal charge = 0

Hono lewis structure angle

The angle which is formed between the central atom with its neighboring atoms The bond angle is also unique for every molecule. Let’s find out the bond angle for hono.

The bond angle for the hono lewis structure is 1200 which is the best fit for bent shape structure. The angle of 1200  between the atoms is giving sufficient space between the lone pairs present on the oxygen and nitrogen atoms so that lesser repulsions will take place between the atoms.

Hono lewis structure octet rule

According to the octet rule, each atom should possess a stable configuration after the bond establishment. Let’s examine whether the HONO lewis structure obeys the octet rule or not.

The hono satisfied the octet rule as the central nitrogen atom has a total stable electronic configuration with 8 electrons whereas the hydrogen also attains a filled outer-most shell with 2 electrons and the remaining two oxygen atoms contain 8 electrons in their octet.

Hence, it is clear that Hono obeys octet as each atom contains 8 electrons in its outermost shell except for the hydrogen atom which contains only 2 as it has only 1s orbitals.

Hono lewis structure lone pairs

 Lone pairs are those pairs of electrons which do not participate in the bonding during bond during bond formation.

In hono lewis structure,  10 lone pairs are associated with the structure. Nitrogen has 2 lone pairs whereas the oxygen atoms comprise the rest of the 8 lone pairs.

The lone pairs present in the hono structure can also show delocalization which adds stability to the system.

Hono valence electrons

Valence electrons are those electrons which are available for bonding. Let’s see how many valence electrons are available for bonding in hono.

The hono lewis structure contains a total of 18 valence electrons as 1 comes from the hydrogen atom, 5 from the nitrogen atom and 6 electrons from each oxygen atom in the structure ie. oxygen provides a total of 12 electrons in the bonding.

  • H ( Z= 1) = 1s1 ie. one electron is present
  • N (Z = 7) =   [Ne] [He] 2s22p3ie. 5 valence electrons are there for nitrogen atom
  • O (Z =8 ) = [He] 2s²2p⁴ ie. 6 electrons for each oxygen atom.
  •  Hence, in this way, we get total valence electron count  = 5 + 6*2 + 1 = 18

Hono hybridization

Hybridization of any molecule can be found by  using  the above equation as mentioned above;

The hybridization of hono is sp2. The hybridization can be found by using the formula;  H= 1/2[V+M-C+A] and the H  comes out to be 3 which indicated the sp2 hybridization.

 According to the above-mentioned formula

  • V = Number of valence electrons on central atom ie. 5
  • M = Number of monovalent atom =1
  • C = Charge on the cation = 0
  • A =  Charge on anion = 0
  • H = ½[5 + 1]
  • H = 3, Hence hybridization is Sp2.

How and why the hybridization of hono is sp2?

The sp2 hybridization of hono indicates that two p and one s orbital are involved in the hono formation. Let’s discuss the sp2 hybridization of hono.

The central nitrogen atom in hono involves its s and two p orbitals to form bonds with the oxygen atoms is shown in the above self-explanatory figure.

Hono solubility

 The solubility factor is an important aspect of any organic molecule as it tells whether the intended compound is soluble in the desired solvent or not.

Hono is a weak acid and an important factor in deciding the nature of its solubility. As it dissociated partially so it reacts with strong bases like Na, Li and K and is always found in solutions only.

Is Hono soluble in water?

Water is a universal solvent as most compounds are soluble in water. Let’s figure out whether the hono is soluble in water or not.

Hono is soluble in water as in the case of hono, when water is added the reaction takes place as the H of the hono gets abstracted by the H20 and the reaction comes out like:

HONO + H2O  =   H3O++ N02(aq)

When hono is soluble in water is also called aqueous hono acid.

Why and how hono is soluble in water?

The solubility of any molecule is depend upon the nature of the bonding shared by the atoms in the that intended molecule.

Hono can be dissolved in water easily because of the formation of hydronium ion as H atom from the hono reacts with water.

Is hono polar or nonpolar?

 The polar and nonpolar nature of any molecule is decided by two factors ie. molecular geometry and its structure shape. Let’s find out the polarity of the hono.

Hono is polar in nature. This is because the structure is unsymmetrical and it contains  4 atoms with large electronegative differences which led to the polar nature of the hono.

Due to the polar nature of hono, it is soluble in all polar solvents.

Why and how hono is polar?

Polarity originates due to the unequal arrangements of the shared electron pairs present in the molecule.

The polarity characteristic of hono is attributed to the oxygen atoms attached to the nitrogen atom as one oxygen atom attached via single bond and other one through the double bond. This arrangement causes the unordered type of arrangement in hono structure.


In hono, nitrogen is directly bonded to two oxygen atoms and one hydrogen atom indirectly and has a bent shape with a perfect 1200 along with sp2 hybridization. The intended molecule is polar in nature.

Pomila Sharma

Hello...Myself is Pomila Sharma. I have done my master's in Chemistry with a specialization in synthetic organic chemistry. I have published 4 research articles. I am very passionate about the chemistry world. I believe it's all about chemistry so let’s explore it together. LinkedIn link: https://www.linkedin.com/in/pomila008

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