Number of C2 axes in CCl4: 3

The molecule CCl4, also known as carbon tetrachloride, belongs to the tetrahedral point group (Td) symmetry. Td is one of the 32 point groups in three-dimensional space, which describes the symmetry elements of a molecule. In the case of CCl4, it has several symmetry elements, including C2 axes.

Understanding C2 axes:
A C2 axis, also known as a two-fold rotation axis, is a symmetry element that represents a rotation of 180 degrees around an axis through the center of the molecule. It indicates that the molecule remains unchanged after a 180-degree rotation.

Identifying C2 axes in CCl4:
To determine the number of C2 axes in CCl4, we need to analyze its molecular structure. CCl4 consists of a central carbon atom bonded to four chlorine atoms, arranged in a tetrahedral geometry.

Visual representation of CCl4:

```
Cl
|
Cl — C — Cl
|
Cl
```

Identifying C2 axes:
1. The molecule has a C2 axis passing through the carbon atom and the center of opposite chlorines.
2. There are three such C2 axes in CCl4, passing through the carbon-chlorine bonds opposite to each other.

Explanation:
The presence of a C2 axis means that the molecule is rotationally symmetric with respect to that axis. In the case of CCl4, the molecule can be rotated 180 degrees around any of the three C-C bonds, and it will be superimposable on itself.

Therefore, the correct answer is that CCl4 has 3 C2 axes based on its tetrahedral symmetry.