Redox Reactions And Electrochemistry Ques 186
Question: The standard potential at $ 25^{o}C $ for the following half reactions are given against them $ Z{n^{2+}}+2e\to Zn,E^{o}=-0.762V $ $ M{g^{2+}}+2e\to Mg,E^{o}=-2.37V $ When zinc dust is added to the solution of $ MgCl_2 $ [UPSEAT 2001]
Options:
A) $ ZnCl_2 $ is formed
B) Zinc dissolves in the solution
C) No reaction takes place
D) $ Mg $ is precipitated
Show Answer
Answer:
Correct Answer: C
Solution:
$ \overset{0}{\mathop{Zn}},+\overset{+2,}{\mathop{MgCl_2}},\to \overset{+2,}{\mathop{ZnCl_2}},+Mg $ No reaction This type of reaction does not occur because $ M{g^{2+}}E^{o}=-2.37V $ while $ Z{n^{2+}}E^{o}=-0.76V $ .
