Redox Reactions And Electrochemistry Ques 153
Question: A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of 2.7 volts. If the standard reduction potential of copper electrode is + 0.34 volt that of magnesium electrode is [KCET 1989]
Options:
A) + 3.04 volts
B) - 3.04 volts
C) + 2.36 volts
D) - 2.36 volts
Show Answer
Answer:
Correct Answer: D
Solution:
Mg lies above Cu in electrochemical series and hence Cu electrode acts as cathode $ E_{cell}^{o}=E_{C{u^{++}}/Cu}^{o}-E_{M{g^{++}}/Mg}^{o} $
$ 2.70V=0.34-E_{M{g^{++}}/Mg}^{o} $ ; $ E_{M{g^{++}}/Mg}^{o}=-2.36V $ .
