Refrigerants Exam with Questions and Answers

Refrigerants Exam with Questions and Answers Which of the following best explains why chlorofluorocarbon (CFC) refrigerants are associated with high ozone depletion potential? a. They contain only hydrogen and fluorine, which directly destroy ozone b. They have strong hydrogen bonding that increases stratospheric reactivity c. They contain chlorine atoms that, upon UV photolysis, release radicals catalytically destroying ozone d. They are highly polar molecules that absorb ozone directly Correct Answer: c Rationale: CFCs contain carbon–chlorine bonds that are broken by ultraviolet radiation in the stratosphere, releasing chlorine radicals. These radicals participate in catalytic cycles that destroy large amounts of ozone without being consumed, making them highly damaging despite low concentrations. Which molecular property most strongly explains higher solubility of certain refrigerants in non-polar lubricating oils? a. High ionic character and strong lattice energy b. Similar non-polar molecular structure and weak dipole moment c. Presence of hydrogen bonding networks in liquid phase d. High molecular polarity and strong dipole-dipole forces Correct Answer: b Rationale: Non-polar refrigerants dissolve better in non-polar oils due to “like dissolves like” principles. Weak dipole moments and similar molecular dispersion forces enhance miscibility, especially important for lubricant-refrigerant compatibility.