The number of electron pairs involved in the formation of hydrogen cyanide molecule are

Options

A. 2
B. 8
C. 3
D. 4

Answer

To determine the number of electron pairs involved in the formation of the hydrogen cyanide (HCN) molecule, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of HCN**:
- The molecular formula for hydrogen cyanide is HCN. In terms of structure, it consists of a hydrogen atom (H) bonded to a carbon atom (C), which is then triple-bonded to a nitrogen atom (N). Therefore, the structure can be represented as H-C≡N.

2. **Determine the Bonds Present**:
- In the HCN molecule, there is:
- One single bond between hydrogen (H) and carbon (C).
- One triple bond between carbon (C) and nitrogen (N).

3. **Count the Electron Pairs**:
- Each bond is formed by a pair of electrons:
- The single bond (H-C) involves **1 pair of electrons**.
- The triple bond (C≡N) involves **3 pairs of electrons**.
- Therefore, to find the total number of electron pairs involved in the formation of HCN, we add the pairs from both types of bonds:
- Total pairs = 1 (from H-C) + 3 (from C≡N) = **4 pairs of electrons**.

4. **Conclusion**:
- The total number of electron pairs involved in the formation of the hydrogen cyanide molecule is **4 pairs of electrons**.

### Final Answer:
The number of electron pairs involved in the formation of hydrogen cyanide molecule is **4 pairs**.

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