The H - C -H bond angle in ethene is …………

Answer

To determine the H-C-H bond angle in ethene, we can follow these steps:

### Step 1: Identify the Structure of Ethene
Ethene (C2H4) is an alkene with a double bond between the two carbon atoms. The molecular structure can be represented as:

```
H H
\ /
C=C
/ \
H H
```

### Step 2: Determine the Hybridization of Carbon Atoms
In ethene, each carbon atom is bonded to two hydrogen atoms and one other carbon atom. This gives each carbon atom a total of three regions of electron density (two single bonds with hydrogen and one double bond with the other carbon).

- The hybridization of carbon in this case is sp², as it involves three regions of electron density.

### Step 3: Analyze the Geometry
The geometry associated with sp² hybridization is trigonal planar. This means that the atoms bonded to the carbon atoms will arrange themselves in a plane to minimize electron pair repulsion.

### Step 4: Determine the Bond Angle
In a trigonal planar arrangement, the bond angles between the atoms are approximately 120 degrees. Therefore, the H-C-H bond angle in ethene is:

**H-C-H bond angle = 120 degrees**

### Final Answer
The H-C-H bond angle in ethene is **120 degrees**.

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