MCAT General Chemistry Question 189: Answer and Explanation
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Question: 189
9. Based on the reaction mechanism shown below, which of the following statements is correct?
2 NO + O2 → 2 NO2
1) 2 NO → N2O2 (fast)
2) N2O2 + O2 → 2 NO2 (slow)
- A. from left to right, because the decrease in electronegativity would make it easier to lose electrons.
- B. from left to right, because the decrease in atomic radius would result in more stable positive ions.
- C. from right to left, because the decrease in ionization energy would make it easier to lose electrons.
- D. from right to left, because the decrease in electron affinity would result in more stable positive ions.
Correct Answer: C
Explanation:
C Choice A is eliminated because electronegativity increases from left to right on the periodic table. Choice B is eliminated because the stability of positive ions increases as you go up and to the left on the periodic table. Finally, choice D is eliminated since electron affinity is the energy released upon gaining an electron and does not relate to the stability of a positive ion. Choice C is the correct answer because ionization energy, or the energy required to remove an electron, decreases from right to left due to a decrease in effective nuclear charge.