Consider the following statements`:`
`I.` A sigma`(sigma)` bond is formed when two`sigma-` orbitals overlap
`II.` A pi`(pi)` bond is formed when two` pi-` orbitals axially
`III.` A `sigma-` bond is weaker than `pi-`bond
Which of the above statements is`//` are correct ?

Options

A. I and II
B. II and III
C. I atone
D. II alone

Explanation

To determine which of the statements regarding sigma and pi bonds are correct, we will analyze each statement one by one.

### Step 1: Analyze Statement I
**Statement I:** A sigma (σ) bond is formed when two sigma (σ) orbitals overlap.

- **Explanation:** A sigma bond is indeed formed when two orbitals overlap along the internuclear axis. This can occur with s orbitals, p orbitals, or hybrid orbitals. The effective overlap along this axis leads to the formation of a sigma bond. Therefore, this statement is **correct**.

### Step 2: Analyze Statement II
**Statement II:** A pi (π) bond is formed when two pi (π) orbitals axially overlap.

- **Explanation:** A pi bond is formed when two p orbitals overlap **side-on**, not axially. The axial overlap refers to the overlap along the internuclear axis, which actually leads to the formation of a sigma bond. Hence, this statement is **incorrect**.

### Step 3: Analyze Statement III
**Statement III:** A sigma (σ) bond is weaker than a pi (π) bond.

- **Explanation:** In terms of bond strength, sigma bonds are generally stronger than pi bonds. This is because sigma bonds have a greater extent of orbital overlap, leading to a higher electron density between the nuclei of the bonded atoms. In contrast, pi bonds have less effective overlap, resulting in weaker bonds. Therefore, this statement is also **incorrect**.

### Conclusion
After analyzing all three statements:
- Statement I is correct.
- Statement II is incorrect.
- Statement III is incorrect.

Thus, the correct answer is that **only Statement I is correct**.