CBr4 has a higher boiling point than CCl4.
The correct answer and explanation is :
Answer:
CBr4 (carbon tetrabromide) has a higher boiling point than CCl4 (carbon tetrachloride). This is due to differences in the strength of intermolecular forces, particularly the London dispersion forces.
Explanation:
The boiling point of a compound is largely determined by the strength of the intermolecular forces between its molecules. To boil, these forces must be overcome, and stronger intermolecular forces result in a higher boiling point. In the case of CBr4 and CCl4, both are nonpolar molecules with similar structures, but the key difference lies in the size and mass of the halogen atoms bonded to carbon.
- Molecular Size and Mass:
- CBr4 has bromine (Br) atoms, which are much larger and heavier than chlorine (Cl) atoms in CCl4. Bromine has a greater atomic mass and a larger electron cloud compared to chlorine. Larger atoms have more electrons, which increases the strength of London dispersion forces (a type of van der Waals force). These forces arise from temporary dipoles that form when electron density fluctuates, and larger atoms have a more pronounced effect, leading to stronger intermolecular attraction.
- London Dispersion Forces:
- The strength of London dispersion forces increases with the size of the atoms involved. Since bromine is larger and heavier than chlorine, CBr4 molecules experience stronger London dispersion forces than CCl4 molecules. As a result, more energy is required to separate CBr4 molecules, resulting in a higher boiling point.
- Boiling Points:
- The boiling point of CBr4 is 260°C, while that of CCl4 is 76°C. The stronger intermolecular forces in CBr4 require more heat energy to overcome, leading to its higher boiling point compared to CCl4.
In summary, the higher boiling point of CBr4 compared to CCl4 is primarily due to the stronger London dispersion forces arising from the larger and more massive bromine atoms.
Now, I’ll generate an image to visualize the molecular structures and atomic sizes of CBr4 and CCl4.
