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MDCAT
Biology
2003

Biology · Man and His Environment

Work through this past-paper style MCQ, then read the full explanation. Practice more biology questions on mMCQ with adaptive drills and topic analytics.

Question

Depletion of ozone layer is due to CFC which release ________.

Options
  • A

    Cl atoms

  • B

    CO

  • C

    F

  • D

    CCl4

Explanation

CFCs do not easily react with other substances. In fact, they break up only through sunlight, which divides their molecules, causing the release of chlorine (Cl). Once the chlorine is released, it is able to react with ozone (O3), to form chlorine monoxide (ClO) and oxygen (O2).

CFCs do not easily react with other substances. In fact, they break up only through sunlight, which divides their molecules, causing the release of chlorine (Cl). Once the chlorine is released, it is able to react with ozone (O3), to form chlorine monoxide (ClO) and oxygen (O2).

Option B is incorrect because CO is not released by CFC as it is composed of chlorine, fluorine and carbon.

Option C is incorrect as fluorine upon its release reacts to form hydrogen fluoride which is a very stable compound. Thus, it does not contribute to ozone depletion.

Option D is incorrect as CCl4 is not produced upon the decomposition of CFCs. Rather, some CFCs are produced from CCl4.

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Tagged under Biology · Man and His Environment · 2003