Why sodium oxide is a solid at room temperature whereas sulfur trioxide is a low boiling point liquid?
The difference in the physical states of sodium oxide (Na2O) and sulfur trioxide (SO3) at room temperature is mainly attributed to their respective chemical properties and bonding.
Sodium oxide (Na2O) consists of sodium cations (Na+) and oxide anions (O2-) held together by ionic bonds. Ionic compounds typically have high melting and boiling points due to the strong electrostatic forces between the oppositely charged ions. These attractive forces require a large amount of energy to overcome, resulting in the solid state of sodium oxide at room temperature.
On the other hand, sulfur trioxide (SO3) is a covalent compound composed of sulfur (S) and oxygen (O) atoms. The bonding in SO3 involves sharing of electrons between the sulfur and oxygen atoms, creating covalent bonds. Covalent compounds generally have lower melting and boiling points compared to ionic compounds. The intermolecular forces between covalent molecules (in this case, SO3 molecules) are weaker than the ionic bonds in Na2O. These weaker intermolecular forces require less energy to break, which leads to the lower boiling point of sulfur trioxide. Therefore, it exists as a liquid rather than a solid at room temperature.
To summarize, the difference in physical states between sodium oxide and sulfur trioxide can be explained by the nature of their chemical bonding. Sodium oxide has ionic bonding and therefore exists as a solid at room temperature, while sulfur trioxide has covalent bonding and has a lower boiling point, resulting in a liquid state at room temperature.