Formal Charges
Formal charges have an important role in organic chemistry since this concept helps us to know whether an atom in a molecule is neutral/bears a positive or negative charge. Even if some molecules are neutral, the atoms within that molecule need not be neutral atoms.
Polarity Of Water
In simple chemical terms, polarity refers to the separation of charges in a chemical species leading into formation of two polar ends which are positively charged end and negatively charged end. Polarity in any molecule occurs due to the differences in the electronegativities of the bonded atoms. Water, as we all know has two hydrogen atoms bonded to an oxygen atom. As oxygen is more electronegative than hydrogen thus, there exists polarity in the bonds which is why water is known as a polar solvent.
Valence Bond Theory Vbt
Valence bond theory (VBT) in simple terms explains how individual atomic orbitals with an unpaired electron each, come close to each other and overlap to form a molecular orbital giving a covalent bond. It gives a quantum mechanical approach to the formation of covalent bonds with the help of wavefunctions using attractive and repulsive energies when two atoms are brought from infinity to their internuclear distance.
![**Question:** How many sigma bonds does the following molecule have?
![Molecule Diagram]
**Options:**
A. 9
B. 3
C. 8
D. 4
**Explanation of Diagram:**
The diagram presented displays a molecular structure commonly found in organic chemistry. It consists of a visual representation of atoms and bonds:
- One oxygen atom.
- Three carbon atoms, forming the backbone of the molecule.
- Single and double bonds between the carbon atoms.
**Explanation:**
To determine the number of sigma bonds, count the single bonds in the molecule, as each single bond represents one sigma bond:
- There is one sigma bond between each pair of bonded atoms in a single bond configuration.
- Double bonds consist of one sigma bond and one pi bond.
By analyzing the structure:
- Oxygen is connected to the carbon by one sigma bond.
- Carbon atoms also have single bonds connecting them.
Given this, you can count a total of 7 sigma bonds in the molecule. Therefore, the correct answer would be:
**Correct Answer:** C. 8](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff1d2ed3e-5db6-4b34-adcc-843852a358f0%2F3142def3-5522-4ff3-a015-f20b94144aa5%2Frm5o8ng_processed.jpeg&w=3840&q=75)
#### Answer Choices
- 8 sigma bonds and 5 pi bonds
- 8 sigma bonds and 5 pi bonds
- 13 sigma bonds and 5 pi bonds
- 13 sigma bonds and 4 pi bonds
### Explanation
This is a structural diagram of benzonitrile. Benzene ring (C₆H₅) is bonded to a nitrile group (−C≡N).
- **Sigma Bonds (σ):** These are single bonds formed by the end-to-end overlap of atomic orbitals.
- **Pi Bonds (π):** These are double or triple bonds formed by the side-to-side overlap of atomic orbitals.
#### Detailed Breakdown:
- **Benzene Ring:** Each of the six carbon atoms in the benzene ring forms three sigma bonds (one with a hydrogen atom if applicable and two with other carbon atoms) and has three pi bonds shared among the alternating double bonds.
- **Nitrile Group:** The nitrile group (−C≡N) contains one sigma bond between the carbon and nitrogen and two pi bonds as part of the triple bond.
### Calculate the Total Bonds
1. **Sigma Bonds:**
- Benzene ring: 6 C-C sigma bonds + 6 C-H sigma bonds (internal bonds)
- Nitrile group: C-C sigma bond + C-N sigma bond
- Total sigma bonds = 8 (in benzene) + 2 (in nitrile group) = 10.
2. **Pi Bonds:**
- Benzene ring: 3 pi bonds
- Nitrile group: 2 pi bonds
- Total pi bonds = 3 (in benzene) + 2 (in nitrile group) = 5.
### Correct Answer
- **13 sigma bonds** and **5 pi bonds**
By analyzing the molecule and understanding the types of bonds, we identified the correct answer.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff1d2ed3e-5db6-4b34-adcc-843852a358f0%2F3142def3-5522-4ff3-a015-f20b94144aa5%2Fz5c1heu_processed.jpeg&w=3840&q=75)
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