Final answer:
Silane (SiH4), phosphine (PH3), and hydrogen sulfide (H₂S) have different melting points, indicating differences in their polar character and intermolecular attractions.
Step-by-step explanation:
The distinct melting points of silane (SiH4), phosphine (PH3), and hydrogen sulfide (H₂S) (-185 °C, -133 °C, and -85 °C, respectively) indicate variations in their polar nature and intermolecular interactions. If silane has a lower melting point than phosphine and hydrogen sulfide, it means that its intermolecular forces are weaker and its polar character is less pronounced. On the other hand, the greater melting points of hydrogen sulfide and phosphine indicate more polarity and stronger intermolecular interactions.