How many `sigma` and `pi` bonds are present in the molecule of ethene ?

Answer

To determine the number of sigma and pi bonds in the molecule of ethene (C2H4), we can follow these steps:

### Step 1: Draw the Structure of Ethene
Ethene has the following structure:
```
H H
\ /
C=C
/ \
H H
```
In this structure, there are two carbon atoms connected by a double bond, and each carbon is also bonded to two hydrogen atoms.

### Step 2: Identify the Types of Bonds
- **Single Bonds**: Each single bond consists of one sigma bond.
- **Double Bonds**: Each double bond consists of one sigma bond and one pi bond.
- **Triple Bonds**: Each triple bond consists of one sigma bond and two pi bonds.

### Step 3: Count the Bonds in Ethene
1. **C=C Double Bond**:
- This double bond contributes **1 sigma bond** and **1 pi bond**.
2. **C-H Bonds**:
- Each carbon atom is bonded to two hydrogen atoms, resulting in **4 C-H single bonds**. Each of these bonds contributes **1 sigma bond**.

### Step 4: Total Count of Sigma and Pi Bonds
- From the double bond (C=C):
- Sigma bonds = 1
- Pi bonds = 1
- From the four C-H bonds:
- Sigma bonds = 4

Now, we can add them up:
- Total Sigma Bonds = 1 (from C=C) + 4 (from C-H) = **5 sigma bonds**
- Total Pi Bonds = 1 (from C=C) = **1 pi bond**

### Final Answer
In the molecule of ethene (C2H4), there are **5 sigma bonds** and **1 pi bond**.

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