Home > Chemistry MCQ: Questions and Answers for Competitive Exams > Which one of the following chemical substances exists as a gas under ordinary conditions and room temperature?

Which one of the following chemical substances exists as a gas under ordinary conditions and room temperature?

A
  

CI4

B
  

CF4

C
  

CCI4

D
  

CBr4

Correct Answer: B

CF4

CF4 (Carbon Tetrafluoride) is the only substance among the given options that exists as a gas under ordinary conditions and room temperature. The reason lies in its extremely low molecular weight and very weak van der Waals forces between its molecules, which means very little energy is needed to keep it in gaseous form.

  • Molecular Weight: CF4 has a very low molecular weight of just 88 g/mol, making it the lightest carbon tetrahalide compound
  • Boiling Point: Extremely low boiling point of -127.8°C, which is why it remains comfortably in gaseous state at room temperature
  • Van der Waals Forces: Very weak intermolecular forces between CF4 molecules due to small size of fluorine atoms, keeping it gaseous
  • Physical Appearance: Colourless, odourless, non-toxic, and non-flammable gas under ordinary conditions
  • Key Principle: Fluorine being the smallest and lightest halogen gives CF4 the lowest molecular weight and weakest intermolecular forces among all carbon tetrahalides

Related Questions