Question

Which of the following statements is correct? (1) If bond order is zero or negative the molecule formed is unstable. (2) If bond order is positive, the bond formed is stable. (3) Bond dissociation energy is directly proportional to the bond order. (4) All arc correct.

Short answer

All statements are correct.

Step-by-step solution

Understanding Bond Order

Bond order is a number that indicates the strength and stability of a bond. It is defined as the difference between the number of bonding electrons and antibonding electrons divided by two.

Checking Statement 1

If the bond order is zero or negative, it generally means that there are not enough bonding interactions to hold the molecule together, making it unstable.

Checking Statement 2

A positive bond order indicates a stable bond because there are more bonding electrons than antibonding electrons.

Checking Statement 3

Bond dissociation energy, which is the energy required to break a bond, is directly proportional to the bond order. Higher bond order means stronger and more stable bond, therefore higher bond dissociation energy.

Conclusion

Based on the previous steps, all the given statements (1, 2, and 3) are correct. Thus, the correct answer is statement 4: All are correct.

Key concepts

Molecular Stability

Molecular stability is an important concept in chemistry. It refers to how likely a molecule is to remain unchanged over time.

When we talk about the stability of a molecule, we often refer to its bond order. Bond order is a way to describe the stability and strength of a chemical bond. It is calculated as the difference between the number of bonding electrons and the number of antibonding electrons, divided by two.

If the bond order is zero or negative, the molecule is generally unstable. This means that there are not enough bonding interactions to keep the molecule together, and it may break apart easily.

On the other hand, if the bond order is positive, the molecule is stable. This positive value indicates that there are more bonding electrons than antibonding electrons, which helps hold the molecule together.

Bond Dissociation Energy

Bond dissociation energy (BDE) is the energy required to break a chemical bond. It gives us an idea of how strong a bond is. The higher the bond dissociation energy, the stronger the bond.

There is a direct relationship between bond dissociation energy and bond order. As the bond order increases, the bond dissociation energy also increases. This means that molecules with higher bond orders require more energy to break their bonds. This is because higher bond orders indicate a stronger and more stable bond.

For instance, a molecule with a bond order of 3 will have a higher bond dissociation energy compared to a molecule with a bond order of 1. This means it's harder to break the bond in the first molecule compared to the second one.

Bond Strength

Bond strength refers to how strong a chemical bond is. It is often measured in terms of bond dissociation energy. A stronger bond requires more energy to break.

The strength of a bond is crucial for understanding how molecules behave in different chemical reactions. Stronger bonds are usually more stable and less reactive, while weaker bonds can break more easily and participate in more reactions.

Bond strength is directly related to bond order. A higher bond order indicates a stronger bond because there are more bonding interactions holding the atoms together.

To summarize:

• Higher bond order → Higher bond strength
• Lower bond order → Lower bond strength

Understanding these relationships helps us predict the stability and reactivity of different molecules in various chemical processes.