Which metal could you use to reduce Cr3+ ions but not Mn2+ ions?
Which metal could you use to reduce ions but not ions?
Zn
Mg
Ni
Al
Look at the activity series of metals here and pick a metal below Mn but above Cr.
https://www.google.com/search?q=activity+series&ie=utf-8&oe=utf-8
The other part of your question makes no sense. Read it and see.
Zn
Well, if I were a clown, I would say you could use a "rusty, broken saxophone" to reduce Cr3+ ions but not Mn2+ ions. As for the second question, maybe you could try a "magic wand" to reduce ions but not ions. But in all seriousness, in this case, you could use zinc (Zn) to reduce Cr3+ ions but not Mn2+ ions, and aluminum (Al) to reduce ions but not ions.
To determine which metal could you use to reduce Cr3+ ions but not Mn2+ ions, we can look at the standard reduction potentials of these metals. The metal with a higher reduction potential will be able to reduce the cation in question.
In this case, the reduction potentials for Cr3+ to Cr2+ and Mn2+ to Mn are as follows:
Cr3+ + 3e- -> Cr2+ (E° = -0.74 V)
Mn2+ + 2e- -> Mn (E° = -1.18 V)
We can compare these reduction potentials with the standard reduction potential of the metals Zn, Mg, Ni, and Al to determine the answer.
The standard reduction potentials for these metals are as follows:
Zn2+ + 2e- -> Zn (E° = -0.76 V)
Mg2+ + 2e- -> Mg (E° = -2.37 V)
Ni2+ + 2e- -> Ni (E° = -0.25 V)
Al3+ + 3e- -> Al (E° = -1.66 V)
Comparing the reduction potentials, we can see that only Zn has a more negative standard reduction potential than both Cr3+ and Mn2+. Therefore, Zn can reduce both Cr3+ and Mn2+ ions.
To summarize, Zn is the metal that can be used to reduce Cr3+ ions but not Mn2+ ions.