HOCl (Hypochlorous Acid) Lewis Structure

Lewis structure of HOCl (Hypochlorous Acid) molecule contains O-H bond and O-Cl bond. So, chlorine atom is the center atom in HOCl molecule. There are three lone pairs on chlorine atom and two lone pairs on oxygen atom. There are no charges on atoms. We will learn how to draw lewis structure of hypochlorous acid step by step in this tutorial.

HOCl lewis structure

HOCl hypochlorous acid lewis structure

HOCl has a very simple structure which contains only O-Cl bond and O-H bond. But, there are very interesting facts on drawing the lewis structure of HOCl.

Steps of drawing lewis structure of HOCl

There are several steps to draw the lewis structure of HOCl. Those steps are explained in detail in next sections. Because HOCl molecule is a simple molecule, some of these steps are not used. In such cases, they are mentioned with those respective steps.

  1. Find total number of electrons of the valance shells of hydrogen, oxygen and chlorine atoms
  2. Determine total electrons pairs as lone pairs and bonds
  3. Find center atom and basic sketch
  4. Mark lone pairs on atoms
  5. Mark charges on atoms if there are charges.
  6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.

Total number of electrons of the valance shells of HOCl

There are 3 elements in HOCl; hydrogen, oxygen and sulfur. Hydrogen is a group IA element and has only one electron in its last shell (valence shell). Oxygen is a group VIA element in the periodic table and contains six electrons in its last shell. Chlorine has 7 valence electrons in its valence shell. Now we know how many electrons are includes in valence shells of hydrogen, oxygen and chlorine atoms.

  • valence electrons given by hydrogen atom = 1 * 1 = 1
  • valence electrons given by oxygen atom = 6*1 = 6
  • valence electrons given by chlorine atoms = 7 * 1 = 7

  • Total valence electrons = 1 + 6 + 7 = 14

Total valence electrons pairs

Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells

Total electron pairs are determined by dividing the number total valence electrons by two. For, HOCl, Total pairs of electrons are 7 (=14/2) in their valence shells.

Center atom and basic skeletal of HOCl

To be the center atom, ability of having greater valance and being more electropositive are important facts. We know, there is no chance for hydrogen to be the center atom because hydrogen's only valence is one.

Wen we consider oxygen atom, oxygen atom should make at least 2 bonds to fulfill its octal. Chlorine has different valence, 1, 3, 5 and 7. So chlorine atom can make single bonds to make compounds.

Therefore, oxygen atom should be the center atom because at least there should be two bonds to make a stable compound. Basic skeletal of HOCl molecule is given below.

HOCl basic structure

Lone pairs on atoms

After deciding the center atom and skeletal of HOCl, we can start to mark lone pairs on atoms. Remember that, there are total of 7 electron pairs (bonds + lone pairs) to mark on atoms.

  • There are already two bonds (one O-H and O-Cl) in the above drawn sketch. Now only 5 (7-2) electron pairs are remaining to mark on atoms.
  • Usually, those remaining electron pairs should be started to mark on outside atoms. But in HOCl, we cannot mark lone pairs on hydrogen atom because there are already two electrons in hydrogen atom.
  • Then mark those remaining 5 electrons pairs on chlorine and oxygen atom.
mark lone pairs on hydrogen chlorine oxygen atom in HOCl

Mark charges on atoms and check the stability and minimize charges on atoms by converting lone pairs to bonds

According to the above structure, there are no charges on atoms. Therefore, we don't need to doing the step of reducing charges to get the most stable structure. That means, we have already go the lewis structure of HOCl.


How many lone pairs are there on atoms in HOCl lewis structure?

Chlorine has three lone pairs and oxygen has two lone pairs. Hydrogen does not have lone pairs. Therefore total number of lone pairs of HOCl is five.

Lewis Structures of Molecules