why SHE acts as anode when connected with Cu but as cathode when connected with Zn? explain
Answers
Answer:
In this standard hydrogen electrode, the hydrogen electrode is acting as anode. Therefore, in hydrogen or anode half cell oxidation will take place. Reaction occurring at anode,
H
2
⇌2H
+
+2e
−
, E
0
=0
At cathode reduction should take place. Metals lying below hydrogen in the reactivity series have positive value of reduction potential and are poor reducing agents and good oxidising agents. Thus, they reduce themselves. Among the given metals Cu and Hg lie below H and have positive reduction potentials. Hence, they can act as cathode.
Reaction occurring at cathode,
Cu
+2
+2e
−
⇌Cu(s); E
0
=+0.34V
Hg
+2
+2e
−
⇌Hg(s); E
0
=+0.885V
Explanation:
Answer:
Because SHE electrode behavior depends on the nature of metal it is connected to.
Explanation:
Background Knowledge → Reducing Agents and Oxidizing Agents : Reducing Agents are those elements which reduce other elements and are themselves oxidized. The elements having less potential (negative values) are reducing agents and act as anode. Oxidizing Agents are those elements which oxidize other elements and are themselves reduced. The elements having more potential (positive values) are oxidizing agents and act as cathode. → Reduction Potentials of Given Metals: Here we have H, Cu and Zn The potentials for these metals are: Zn = -0.76 V (least) H = 0.00 V (greater than Zn) Cu = +0.34 V (greatest) → Conclusion: When SHE (Standard Hydrogen Electrode) is connected with Cu, it acts as anode and Cu acts as cathode since H has less potential than Cu. When SHE (Standard Hydrogen Electrode) is connected with Zn, it acts as cathode and Zn acts as anode since Zn has less potential than H. Less potential= Reducing Agent; acts as anode More potential= Oxidizing Agent; acts as cathode - - - Hope it helps <3