To determine which of the given molecules is a non-linear molecule, we will analyze the molecular geometry of each option provided.
### Step-by-Step Solution:
1. **Identify the Molecules**: The molecules we need to analyze are CO2, C2H4, HCN, and H2.
2. **Analyze CO2**:
- CO2 (Carbon Dioxide) has a linear structure.
- It consists of a carbon atom double bonded to two oxygen atoms (O=C=O).
- The bond angle is 180°, confirming its linearity.
3. **Analyze C2H4**:
- C2H4 (Ethylene) also has a linear structure.
- It consists of two carbon atoms connected by a double bond, with each carbon atom bonded to two hydrogen atoms (H2C=CH2).
- The geometry around each carbon atom is planar, and the bond angles are 120°, but overall the molecule is considered linear due to its arrangement.
4. **Analyze HCN**:
- HCN (Hydrogen Cyanide) has a linear structure.
- It consists of a hydrogen atom bonded to a carbon atom, which is triple bonded to a nitrogen atom (H-C≡N).
- The bond angle is also 180°, confirming its linearity.
5. **Analyze H2**:
- H2 (Hydrogen) is a diatomic molecule consisting of two hydrogen atoms bonded together (H-H).
- This molecule has no angles to consider, but it can be described as linear.
6. **Conclusion**:
- All the molecules CO2, C2H4, HCN, and H2 are linear. However, if we consider H2O (not mentioned in the options but often confused), it would be a non-linear molecule due to its bent shape.
- Based on the provided options, none of the listed molecules are non-linear.
### Final Answer:
- None of the given molecules (CO2, C2H4, HCN, H2) is a non-linear molecule.
