The difference in physical state between ammonia and sugar at room temperature boils down to the strength of the intermolecular forces between their molecules.

Ammonia (NH3):

* Weak Intermolecular Forces: Ammonia molecules are polar, meaning they have a slightly positive and slightly negative end due to the uneven sharing of electrons. This polarity allows for weak dipole-dipole interactions. However, these forces are not strong enough to hold the ammonia molecules together in a solid state at room temperature.

* Low Molecular Weight: Ammonia has a relatively low molecular weight, which further contributes to its weak intermolecular forces.

Sugar (C12H22O11):

* Strong Intermolecular Forces: Sugar molecules are large and complex, containing many polar hydroxyl groups (-OH). These groups form strong hydrogen bonds with each other, which hold the sugar molecules tightly together in a solid state.

* High Molecular Weight: Sugar has a high molecular weight, which increases the strength of these intermolecular forces.

In summary:

* Ammonia: Weak intermolecular forces and low molecular weight result in a gaseous state at room temperature.

* Sugar: Strong intermolecular forces (hydrogen bonding) and high molecular weight result in a solid state at room temperature.