Formic acid has the chemical formula HCOOH or CH2O2, with a hydrogen atom bonded to the -COOH group to form the simplest carboxylic acid. It is also known as formic acid.
Did you know that formic acid can occur naturally in various insect species such as ants and stingless bees?
We prepare HCOOH in industry via the below mentioned equations:
CH3OH + CO ——> HCO2CH3 (1)
HCO2CH3 + H2O ——> HCOOH + CH3OH (2)
In laboratory preparation, the necessary chemical reactions are:
C2O4H2 ——-> CO2H2 + CO2
Likewise,
Pb(HCOO)2 + H2S ——-> 2HCOOH + PbS
Formic acid has a molecular weight of 47.018 g/mol and a density of 1.220 g/ml. It appears as a colorless fuming liquid that carries a pungent, penetrating odor.
It is used as fuel cells and also as a mobile phase component of reversed phase high performance liquid chromatography processes.
Apart from that, HCOOH can be used in leather manufacturing and dyeing industry as miticides and antibacterial agents.
Now let's learn about the chemical bonding of this carboxylic acid compound.
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CH2O2-Lewis-Structure
If we want to find out the nature of the chemical bond within a polyatomic molecule, we need to draw the Lewis structure.
Lewis Structure gives us a step-by-step process to sketch the 2D schematic representation of a given molecule. Here we use the concept of valence electrons to figure out the mode of bond formation.
In HCOOH or formic acid we have two hydrogen atoms, one carbon atom and one two oxygen atoms.
Here we have a picture of the modern periodic table.
As we can see, carbon has a valence of 4 and has 4 valence electrons. Oxygen belongs to group 16 (chalcogens) and has 6 valence electrons.
Hydrogen belongs to group 1 and has only 1 electron in its outermost shell (valence electron).
Total number of valence electrons = 1*2 + 4*1 + 6*2 = 18.
Among the three elements, hydrogen has the lowest electronegativity value, carbon comes second, and oxygen has the highest value.
By the general rule, the least electronegative element must occupy the central position.
However, hydrogen is more likely to stay at the corners and not become the central atom because it only has one valence electron.
So we have carbon as the central atom in formic acid.
The atoms look like this:
Now we will place the valence electrons around each constituent atom and the diagram will look like this:
A very necessary concept comes into play here: the octet rule. According to this rule, any element present in groups 1–17 (the main groups) tends to attain octet configuration in their valence shells, like that of the noble gas elements.
For example, nitrogen will tend to have a neon configuration and chlorine will tend to have an argon configuration.
You may have heard that chemistry is full of exceptions, and one such exception is that hydrogen tends to attain helium configuration and therefore requires a total of 2 electrons to fill the valence shell.
In the diagram above we can see that carbon has not yet reached the octet filling state. To do this, we bring two more electrons around the atom.
The required sketch will be:
When we calculate the formal fees:
This is the formula for finding the formal fee values:
Mold fee of C = 4 - 0.5*8 - 0 = 0.
Mold fee for each H = 1 - 0.5*2 - 0 = 0.
Formal charge for O bound to H and C both = 6 – 0.5*4 – 4 = 0.
Shape charge for O bound to C = 6 – 0.5*4 – 4 = 0.
Therefore, the atoms are in their lowest formal charge values.
The most suitable Lewis structure for formic acid is:
CH2O2 molecular geometry
VSEPR stands for Valence Shell Electron Pair Repulsion Theory. This model is used in chemistry to predict the molecular geometry of a given composition from its Lewis structure.
While the Lewis structure gives us a 2D representation of a chemical molecule, the VSEPR model gives us a basis to decipher the 3D molecular shape.
This is relevant for covalently bound molecules. It looks at the pairs of electrons (both bonded and unbonded) and talks about the concept of minimal repulsion.
According to the VSEPR theory, the electrons create a negatively charged atmosphere around the atomic nuclei and this creates a repulsive force between the same charges.
The stability of the molecules is maintained by increasing the distance between the electrons, thus minimizing the repulsive force.
In VSEPR theory, we can predict molecular geometry via VSEPR notations.
AXnEx is the VSEPR notation.
where A stands for the central atom, X for the surrounding atoms (in VSEPR we also consider triple and double bonds as one bonding group),
E stands for the number of lone pairs of electrons bound to the central atom.
Here carbon is the central atom (A). X: 2 oxygen and 1 hydrogen atom,
∴ n = 3.
E: not a lone pair of A, ∴ x = 0.
AX3E0 is the VSEPR notation for formic acid.
As we can see from the graph,the molecular geometry of HCOOH is trigonal-planar.
CH2O2 hybridization
One of the most important models for describing the nature of chemical bonds is orbital hybridization.
The concept of hybridization deals with atomic orbitals (AOs). The same atom's orbitals with equivalent energies come together to combine and merge, forming hybrid orbitals. The valence shell electrons participate. These hybrid orbitals are then considered to be involved in the formation of bonds.
Now let's decipher the hybridization type for formic acid.
Steric number = number of atoms bonded to the central atom within a molecule + number of lone pairs of electrons bonded to the central atom
In HCOOH, the central atom carbon is doubly bonded to an oxygen atom, single bonded to another oxygen atom and a hydrogen atom.
There are no lone or lone pairs of electrons in formic acid.
∴ the steric number = 3 + 0 = 3.
We therefore have sp2 hybridization for carbon.
For the oxygen in C=O we have sp2 hybridization because it has two lone pairs and one bonded atom, while for the oxygen in C-O we have sp3 hybridization because there are 2 lone pairs and 2 sigma bonds.
CH2O2 polarity
Now let's talk about polarity.
Polarity is an important property or property of a chemical molecule. It is related to the distribution of electric charges between the constituent atoms within a molecule.
When can a molecule be called polar? We can call a molecule polar if the distribution of electrons between atoms is not uniform, i.e. there is an asymmetric distribution of charges within the molecular composition.
We can check this using the concept of electronegativity. A difference in electronegativity between two atomic elements in the range of about 0.4 – 2 is considered a polar covalent bond.
Here we have a diagram of the Pauling electronegativity map:
Here, in C-H bond, the difference: 2.55 – 2.20 = 0.35.
For C and O bonding, the difference is: 3.44 – 2.55 = 0.89.
In the O-H bond the difference is: 3.44 - 2.20 = 1.24
As we can see, the inclination of the bonds towards is polar in nature. Also, we have an asymmetric structure so the hydrogen end is on the positive side while the oxygen end is on the negative side.
HCOOH is polar in nature. It is miscible with water and polar organic solvents.
Conclusion
HCOOH is the simplest carboxylic acid and an important organic molecule. We have discussed chemical bonding in detail in this article.
Have fun with your studying!
FAQs
What is the molecular geometry of ch2o? ›
The molecular geometry of CH2O is trigonal planar because the central carbon atom has no lone pair and is attached to the two hydrogen atoms and one oxygen atom through two single bonds and one double bond.
What is the molecules for ch2o2? ›The molecular formula CH2O2 (molar mass: 46.03 g/mol) may refer to: Dihydroxymethylidene.
What type of bond is CH2O2? ›Chemical Structure Description
The formic acid molecule contains a total of 4 bond(s) There are 2 non-H bond(s), 1 multiple bond(s), 1 double bond(s), 1 carboxylic acid(s) (aliphatic) and 1 hydroxyl group(s).
In formaldehyde, CH2O, carbon is the central atom. It has a normal valence of 4. It has four bonds, two single bonds with hydrogen and a double bond with oxygen. The formal charge is therefore 4 - 4 = 0, the carbon has no formal charge in this molecule.
How many sigma bonds are in CH2O? ›Therefore, the formaldehyde molecule contains: 3 sigma bonds and 1 pi bond.
Is H2CO trigonal planar or bent? ›The central atom of H2CO, has three regions of electron density around it. The regions of electrons making a trigonal planar shape, giving a bond angle of 120°. All three of these regions of electrons are bonding so the arrangement of the bonds/molecular shape is trigonal planar.
What is the name of the compound CH2O2? › Is CH2O2 an acid or base? ›Formic acid | CH2O2 | ChemSpider.
What is the molecular name for H2CO2? ›Chemical Carbonous Acid Formula is H2CO2. It is the strongest carboxylic acid.
How do you solve formal charge? ›We can calculate an atom's formal charge using the equation FC = VE - [LPE - ½(BE)], where VE = the number of valence electrons on the free atom, LPE = the number of lone pair electrons on the atom in the molecule, and BE = the number of bonding (shared) electrons around the atom in the molecule.
Is H2CO ionic or covalent? ›
Answer and Explanation: There are two H-C bonds with an EN difference of 0.35. These bonds are pure covalent bonds. The carbon to carbon bonds have an electronegativity difference of 0, so the double C-C is also pure covalent.
Is H2CO hydrogen bonding? ›The conformation of H2CO-H20 is linear hydrogen bonding.
Is CH2O2 a peroxide? ›The molecular formula CH2O2 (molar mass: 46.03 g/mol) may refer to: * Dihydroxymethylidene * Dioxirane, an unstable cyclic peroxide * Formic acid, an organic acid * Methylenedioxy, a functional groupThis set index page lists chemical structure articles associated with the same molecular formula.
What hybridization structure is H2CO? ›H2CO has 2(1) + 4 + 6 = 12 valence electrons. The central carbon atom has a trigonal planar arrangement of the electron pairs that requires sp2 hybridization. The two C−H sigma bonds are formed from overlap of the sp2 hybrid orbitals from carbon with the hydrogen 1s atomic orbitals.
When drawing the Lewis structure of H 2 COH 2 CO molecule What does the structure represent? ›When drawing the Lewis structure of the H,CO molecule, the structure should represent a total of 12 valence electrons. Based on the elements present, a total of electrons are needed for a stable structure. Thus, there should be bonds in the structure.
How many bonding electrons are there in CH2O? ›Total number of valence electrons: Electrons available CH2O C Group 4 4 2 H Group 1 2(1) = 2 O Group 6 6 12 There are 12 electrons available for bonding.
Does CH2O have hydrogen bonding? ›For the interaction between CH2O and H2O, only one configuration was identified, where the CH2O···H2O complex is stabilized by one hydrogen bond formed between the O atom of CH2O and one H atom of water.
How do you determine hybridization? ›An easy way to figure out what hybridization an atom has is to just count the number of atoms bonded to it and the number of lone pairs. Double and triple bonds still count as being only bonded to one atom.
Is CH2O polar or non polar? ›Formaldehyde (CH2O) is a polar compound. This is because of the unbalanced electron density. The electronegativity difference between hydrogen and carbon is negligible, whereas the electronegativity difference between carbon and oxygen is large enough to cause polarity.
How many bonding and lone pairs are in CH2O? ›Thus in the Lewis structure of CH2O, the central Carbon atom forms two single bonds with two Hydrogen atoms and one double bond with an Oxygen atom. Here the octets of both Carbon and Hydrogen are completed, and only Oxygen has two lone pairs of electrons.
What is the full form of CH2O? ›
The chemical formula of formaldehyde is CH2O: it has one carbon (C) atom, two hydrogen (H) atoms and one oxygen (O) atom. Its chemical formula can also be written as HCHO, and its chemical structure is shown here. Chemical Structure of Formaldehyde.
What hybridization is coh2? ›The central carbon in formaldehyde has sp2 hybridization.
The hybrid orbitals make three single bonds to the two hydrogens and one oxygen with the remaining p orbital forming the additional bond with a p orbital of oxygen to yield the double bond.
Formaldehyde molecule (H2CO) shows trigonal planer geometry because it has AX3 type molecule which has carbon atom in the centre which is surrounded by two hydrogens and one oxygen atom with two lone pairs.
What H2CO called? ›Formaldehyde | H2CO - PubChem.
Which of the following is the name of the compound CoS2? ›| PubChem CID | 134068284 |
|---|---|
| Molecular Formula | CoS2-4 |
| Synonyms | Cobalt sulfide (CoS2) DTXSID3065166 |
| Molecular Weight | 123.07 |
| Component Compounds | CID 29109 (Sulfide) CID 104730 (Cobalt) |
Molecular formaldehyde contains a central carbon atom with a double bond to the oxygen atom and a single bond to each hydrogen atom. This structure is summarised by the condensed formula H2C=O.
What hybridization does formic acid have? ›The carbon in formic acid is double bonded to an oxygen, and has two single bonds. This means that it has sp2 hybridization.
Is cho2 an acid or base? ›| PubChem CID | 283 |
|---|---|
| Description | Formate is a monocarboxylic acid anion that is the conjugate base of formic acid. Induces severe metabolic acidosis and ocular injury in human subjects. It has a role as a human metabolite and a Saccharomyces cerevisiae metabolite. It is a conjugate base of a formic acid. ChEBI |
Neutral on the pH scale is 7. This means that the substance is neither acidic nor basic. These substances have an equal amount of hydrogen (H+) and hydroxide ions (OH-). Water and human blood are both common examples of substances with a neutral pH.
What molecule is CoH2? ›What is molecular mass of h2co2? ›
=(1×2) + 12 + (16×2) = 2 +12 + 32 = 46.
Is HCO2H polar? ›Answer and Explanation: The molecule is polar.
What is formal charge short answer? ›Formal Charge Definition:
“The formal charge over an atom of a polyatomic molecule or ion is the difference between the valence electron of that atom in the elemental state and the number of electrons assigned to that atom in Lewis structure.”
In cases where there MUST be positive or negative formal charges on various atoms, the most stable structures generally have negative formal charges on the more electronegative atoms and positive formal charges on the less electronegative atoms.
Does COH2 have polar bonds? ›COH2 lewis structure is a polar molecule. It can be explained on the basis of their electronegativity difference which in this case has O atom the highest electronegativity.
Is COH2 polar? ›Among the species observed to be nonpolar are: (NO)3, (NO)4, N202, NeHCl, COH2, (BF3)2, (BF3)3, (BF3)4.
How many valence electrons does COH2 have? ›In the Lewis structure for COH2 there are a total of 12 valence electrons. You'll need to form a double bond between the Carbon and Oxygen to complete the octet on the Carbon.
What are the 5 steps to drawing Lewis structures? ›- Determine total number of available valence electrons. ...
- Determine structural connectivity. ...
- Draw hypothetical structure with each atom surrounded by 8 electrons in pairs. ...
- Count the total number of electrons in the hypothetical structure. ...
- Determine if any atoms can have less than an octet.
Lewis structures (also known as Lewis dot structures or electron dot structures) are diagrams that represent the valence electrons of atoms within a molecule. These Lewis symbols and Lewis structures help visualize the valence electrons of atoms and molecules, whether they exist as lone pairs or within bonds.
How do you determine the structure of a lewis structure? ›Step 1: Determine the total number of valence electrons. Step 2: Write the skeleton structure of the molecule. Step 3: Use two valence electrons to form each bond in the skeleton structure. Step 4: Try to satisfy the octets of the atoms by distributing the remaining valence electrons as nonbonding electrons.
How do you find the Lewis bond structure? ›
- Count up the total number of valence electrons. ...
- Calculate the total number of electrons that would be needed for each atom to have an octet (or doublet for H).
- Subtract the result of step 1 from the result of step 2. ...
- Assign two bonding electrons to each bond.
Molecular Polarity. To determine if a molecule is polar or nonpolar, it is frequently useful to look at Lewis structures. Nonpolar compounds will be symmetric, meaning all of the sides around the central atom are identical - bonded to the same element with no unshared pairs of electrons.
How many resonance structures does ch2n2 have? ›It has three resonance structures.
What is hybridization Lewis structure? ›Hybridization of Atomic Orbitals. We can use Lewis dot structures to determine bonding patterns in molecules. We can then use VSEPR to predict molecular shapes, based on the valence electron pairs of the Lewis structures. Once we know a molecular shape, we can start to look at the physical properties of compounds.
How do you determine polarity? ›The polarity of a covalent bond can be judged by determining the difference in the electronegativities of the two atoms making the bond. The greater the difference in electronegativities, the greater the imbalance of electron sharing in the bond.
How do you know if a bond is polar? ›Although there are no hard and fast rules, the general rule is if the difference in electronegativities is less than about 0.4, the bond is considered nonpolar; if the difference is greater than 0.4, the bond is considered polar.
How do you count bonding and lone pairs in a Lewis structure? ›- Step 1: Count each single line as one bonded pair of electrons.
- Step 2: Count each double line as two bonded pairs of electrons.
- Step 3: Count each triple line as three bonded pairs of electrons.
- Step 4: Add up the numbers from each step.
Find the number of lone pairs on the central atom by subtracting the number of valence electrons on bonded atoms (Step 2) from the total number of valence electrons (Step 1). Divide the number of VEs not in bonds (from Step 3) by 2 to find the number of LPs.
What are Lewis structures for dummies? ›A Lewis Structure is a very simplified representation of the valence shell electrons in a molecule. It is used to show how the electrons are arranged around individual atoms in a molecule. Electrons are shown as "dots" or for bonding electrons as a line between the two atoms.
What is Lewis structure explain with example? ›A Lewis structure is based on the concept of the octet rule, in which atoms share electrons so that each atom has eight electrons in its outer shell. As an example, an oxygen atom has six electrons in its outer shell.
How do you find the valence electrons in a Lewis structure? ›
- Add together the valence electrons from each atom. (Recall that the number of valence electrons is indicated by the position of the element in the periodic table.)
- If the species is a polyatomic ion, remember to add or subtract the number of electrons necessary to give the total charge on the ion.