Problem 32 - A Complete Resource Book in Chemistry for JEE Main

Question

The molecule having highest bond energy is (a) \(\mathrm{N}-\mathrm{N}\) (b) \(\mathrm{F}-\mathrm{F}\) (c) \(\mathrm{C}-\mathrm{C}\) (d) \(\mathrm{O}-\mathrm{O}\)

Step-by-Step Solution

Answer

The \\( ext{C-C}\\) bond has the highest bond energy.

Step 1: Understanding Bond Energy

Bond energy is the measure of bond strength in a chemical bond. Higher bond energy indicates a stronger bond, which requires more energy to break. To answer this question, we need to compare the bond energies of each pair given.

Step 2: Comparative Bond Energies

Recall that single bonds between atoms like \( ext{N-N}\), \( ext{F-F}\), \( ext{C-C}\), and \( ext{O-O}\) typically have different bond energies based on the elements involved. Standard bond energy values are: \( ext{N-N}\) \(167 \text{ kJ/mol}\), \( ext{F-F}\) \(157 \text{ kJ/mol}\), \( ext{C-C}\) \(348 \text{ kJ/mol}\), and \( ext{O-O}\) \(146 \text{ kJ/mol}\).

Step 3: Identify the Highest Bond Energy

By comparing the bond energies from Step 2: \( ext{C-C}\) bond energy is \(348 \text{ kJ/mol}\), which is higher than \( ext{N-N}\), \( ext{F-F}\), and \( ext{O-O}\). This means the \( ext{C-C}\) bond has the highest bond energy.

Key Concepts

Chemical Bonding

Chemical bonding is the process by which atoms come together to form compounds. This occurs because atoms seek to reach a more stable energy state, often achieved by having a full outer electron shell. There are several types of chemical bonds, including covalent, ionic, and metallic bonds.

• Covalent Bonds: Atoms share electron pairs to complete their outer electron shells and achieve greater stability.
• Ionic Bonds: Atoms transfer electrons to each other, forming charged ions that attract each other.
• Metallic Bonds: Metal atoms share a 'sea' of electrons that hold the atoms together.

Chemical bonding is crucial for the formation of molecules and the diversity of matter we observe in the universe. It helps determine the properties and behavior of various substances.

Covalent Bonds

Covalent bonds are a type of chemical bond where two atoms share one or more pairs of electrons. This sharing allows each atom to achieve a stable electron arrangement. These bonds can be single, double, or triple, depending on how many electron pairs are shared.

• Single Covalent Bonds: One pair of electrons is shared, like in a hydrogen molecule (\( ext{H}_2\)).
• Double Covalent Bonds: Two pairs of electrons are shared, as in an oxygen molecule (\( ext{O}_2\)).
• Triple Covalent Bonds: Three pairs of electrons are shared, such as in nitrogen gas (\( ext{N}_2\)).

Covalent bonds are particularly strong and lead to the formation of molecules. They are key to the molecular structures of organic compounds and form the backbone of many biological molecules. The bond energy is an essential factor in determining the strength and stability of these covalent bonds.

Molecular Stability

Molecular stability refers to how well a molecule can maintain its structure and resist breaking down into its constituent atoms. Several factors contribute to molecular stability, including bond strength, electron configurations, and molecular symmetry.

• Bond Strength: Stronger bonds require more energy to break, leading to more stable molecules.
• Electron Configuration: Molecules with complete electron shells are generally more stable because they have lower potential energy.
• Molecular Symmetry: Symmetrical molecules often have balanced distribution of charge, contributing to stability.

In chemical reactions, molecules with higher stability tend to be less reactive because it requires more energy to disrupt their structure. Understanding molecular stability is crucial for predicting the behavior of molecules in various chemical contexts and is a foundational concept in chemistry.