9701 MCQ Solution 25

Question 25: [Organic > Halogen Derivatives]:

Chlorofluorocarbons (CFCs) have been widely used in aerosol sprays, refrigerators and in making foamed plastics, but are now known to destroy ozone in the upper atmosphere.

Which of the following will not destroy ozone, and therefore can be used safely as a replacement for CFCs?

A CHBr₃

B CCl₃CBr₃

C CHClFCClF₂

D CH₃CH₂CH₂CH₃

Reference: Past Exam Paper – November 2002 Paper 1 Q25

Solution 25:

Answer: D.

Options A, B and C are incorrect because they contain halogen derivatives and may homolytically break down forming halogen free radicals that will react and break down the ozone layer. 

Option D is butane which is completely inert so will not affect the ozone.