The percentage s-character of the hybrid orbitals in methane , ethene are respectively

Options

A. 25,33,50
B. 25,50,75
C. 50,75,100
D. 10,20,40

Answer

To determine the percentage s-character of the hybrid orbitals in methane (CH₄) and ethene (C₂H₄), we can follow these steps:

### Step 1: Identify the Hybridization of Methane (CH₄)
- **Methane Structure**: In methane, carbon forms four single bonds with hydrogen.
- **Steric Number Calculation**: The steric number is calculated as the number of sigma bonds plus the number of lone pairs. Here, there are 4 sigma bonds and 0 lone pairs.
\[ \text{Steric Number} = 4 + 0 = 4 \]
- **Hybridization**: The hybridization corresponding to a steric number of 4 is sp³.

### Step 2: Calculate the Percentage s-character for Methane
- **s-character in sp³**: In sp³ hybridization, there is 1 s orbital and 3 p orbitals.
- **Percentage Calculation**:
\[ \text{Percentage s-character} = \left( \frac{\text{s orbitals}}{\text{total orbitals}} \right) \times 100 = \left( \frac{1}{4} \right) \times 100 = 25\% \]

### Step 3: Identify the Hybridization of Ethene (C₂H₄)
- **Ethene Structure**: In ethene, each carbon forms three sigma bonds (two with hydrogen and one with another carbon) and there is one pi bond between the two carbon atoms.
- **Steric Number Calculation**: The steric number is 3 (3 sigma bonds) + 0 (lone pairs).
\[ \text{Steric Number} = 3 + 0 = 3 \]
- **Hybridization**: The hybridization corresponding to a steric number of 3 is sp².

### Step 4: Calculate the Percentage s-character for Ethene
- **s-character in sp²**: In sp² hybridization, there is 1 s orbital and 2 p orbitals.
- **Percentage Calculation**:
\[ \text{Percentage s-character} = \left( \frac{1}{3} \right) \times 100 \approx 33.33\% \]

### Summary of Results
- **Methane (CH₄)**: 25% s-character
- **Ethene (C₂H₄)**: 33.33% s-character

### Final Answer
The percentage s-character of the hybrid orbitals in methane and ethene are respectively:
- Methane: 25%
- Ethene: 33.33%