MCAT Chemistry Question — Strongest Reducing Agent
- by
- Dec 26, 2014
- MCAT Blog, MCAT Chemistry, MCAT Question of the Day
Given the list of reduction potentials, which of the following species is the strongest reducing agent?
Li+(aq)+ e– →Li (s) Eored = -3.04 V
Zn2+(aq) + 2 e– → Zn (s) Eored = -0.76 V
Ag+(aq) + e– → Ag (s) Eored = 0.80 V
Ce4+(aq) + e– → Ce3+ (s) Eored = 1.44 V
A. Ce4+
B. Zn2+
C. Li
D. Ag
Explanation
This question is testing your understanding of the redox chemistry and reduction potentials. To answer this question, you must first know that a reducing agent is itself oxidized. Therefore, the strongest reducing agent is going to be the species that is most readily oxidized. The Nernst equation, DG = -nFE, shows that a spontaneous reaction (DG < 0) corresponds to an electrochemical potential, E, that is greater than zero.
Since Ce4+ is spontaneously reduced, choice A can be eliminated. Zn2+ is already in its oxidized form and therefore cannot be oxidized further making B the wrong answer. Considering answer choices C and D, you must reverse the reactions to find Eoox, which equals the negative of the reduction potential (Eoox = -Eored). Therefore, the oxidation of Ag(s) is a nonspontaneous reaction while the oxidation of Li(s) proceeds spontaneous with a potential of +3.04 V, making C the correct answer.
Want more MCAT practice?
We’ve got options for every schedule and learning style!
From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT Advisor using the form below. No obligation, just expert advice.
Search the Blog
Free Consultation
Interested in our Online MCAT Course, One-on-One MCAT Tutoring or Med admissions packages? Set up a free consultation with one of our experienced Senior Student Advisors.
Schedule NowPopular Posts
-
MCAT Blog What's on the MCAT?
-
MCAT Blog How to Review MCAT Full Lengths

Free MCAT Practice Account
Need great MCAT practice?Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a half-length diagnostic exam and one of our full-length MCAT practice exams.
Learn More