Boiling as a Physical Change

Steps:

• Recognize boiling as a phase transition from liquid to gas at 58°C for SiCl₄.
• Classify the change: physical if composition unchanged, chemical if new substances form.
• Identify forces involved: covalent Si-Cl bonds remain intact; only intermolecular forces (van der Waals) overcome.
• Match to options: select physical change with intermolecular forces breaking.

Why C is correct:

• Boiling is a physical change by definition, where intermolecular forces break to allow phase transition without altering molecular structure.

Why the others are wrong:

• A: Incorrectly labels as chemical; boiling does not break covalent bonds or form new substances.
• B: Same error as A; chemical change misapplied to a phase transition.
• D: Physical change correct, but Si-Cl bonds do not break—only intermolecular forces do.

Final answer: C