`underset(3)(CH_(2)) = underset(2)(CH) - underset(1)(CN)`
`Cl - C2` bond of this molecules is formed by:

Options

A. `sp^(3) - sp^(2)` overlap
B. `sp^(2) - sp^(3)` overlap
C. `sp- sp^(2)` overlap
D. `sp^(2) - sp^(2)` overlap

Answer

To determine the type of bond formed between the C1 and C2 carbons in the given structure, we will follow these steps:

### Step 1: Identify the Structure
The given structure is CH₂=CH-CN, which can be rewritten as CH₂=CH-C≡N. This indicates that we have a double bond between C1 and C2, and a triple bond between C2 and nitrogen.

### Step 2: Determine the Hybridization of C1 and C2
- **C1 (the first carbon in the double bond)**:
- C1 is bonded to two hydrogens and one carbon (C2) through a double bond.
- The total number of sigma bonds around C1 is 2 (from the two C-H bonds) + 1 (from the C1=C2 bond) = 3 sigma bonds.
- Therefore, the hybridization of C1 is **sp** (since it has 2 pi bonds and 1 sigma bond in the double bond).

- **C2 (the second carbon in the double bond)**:
- C2 is bonded to one hydrogen, one carbon (C1), and one carbon (C3) through a double bond and a triple bond.
- The total number of sigma bonds around C2 is 1 (from C2-H) + 1 (from C2=C1) + 1 (from C2≡C3) = 3 sigma bonds.
- Therefore, the hybridization of C2 is **sp²** (since it has 1 pi bond in the double bond and 2 pi bonds in the triple bond).

### Step 3: Identify the Overlap Type
- The bond between C1 and C2 is formed by the overlap of their hybrid orbitals.
- C1 (sp hybridized) overlaps with C2 (sp² hybridized).
- The type of overlap that occurs between sp and sp² hybridized orbitals is called **sigma (σ) overlap**.

### Conclusion
The bond formed between C1 and C2 carbons is a **sigma bond** due to the sp and sp² overlap.

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