Which selection is an example of a molecule with a linear shape?
A) CO2
B) AlCl3
C) BeBr2
D) NCl3

To determine which molecule has a linear shape, we need to look at the molecular geometry and the bonding arrangements of each option. Let’s analyze them one by one:

1. **\[CO_2\] (Carbon Dioxide)**:
- **Structure**: Carbon dioxide has a central carbon atom double-bonded to two oxygen atoms. The oxygen atoms are on opposite sides of the carbon.
- **Geometry**: The molecule is linear because the bond angle between the oxygen atoms is 180°. This is due to the carbon atom's sp hybridization.

2. **\[AlCl_3\] (Aluminum Chloride)**:
- **Structure**: In the solid state, aluminum chloride forms a polymeric structure, but in the gas phase, it forms a trigonal planar structure around the aluminum atom.
- **Geometry**: The molecular geometry in the gas phase is trigonal planar, not linear.

3. **\[BeBr_2\] (Beryllium Bromide)**:
- **Structure**: Beryllium bromide has a central beryllium atom double-bonded to two bromine atoms.
- **Geometry**: The molecule is linear because the bond angle between the bromine atoms is 180°. This is due to the beryllium atom's sp hybridization.

4. **\[NCl_3\] (Nitrogen Trichloride)**:
- **Structure**: Nitrogen trichloride has a central nitrogen atom bonded to three chlorine atoms.
- **Geometry**: The molecule has a trigonal pyramidal shape because of the lone pair on the nitrogen atom which repels the bond pairs, resulting in a bond angle less than 109.5°.

**Conclusion**: The molecules with a linear shape from the given options are \[CO_2\] and \[BeBr_2\]. Both exhibit a linear geometry.