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Displacement reactions. (1 Viewer)

loser

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How are you supposed to know whether it will happen or not?

For example:
Zinc in lead nitrate solution
Tin in aluminium sulfate solution

etc.
 
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ND

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If the metal being places into the solution has a greater activity than the one in the solution, it will displace it.
 
N

ND

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No, you get a sheet of electrode potentials in the exam.

edit: i should probably explain:

the activity of it is really a measure of how much it wants to lose an electron. look at the standard electrode potentials, they are written as the reduction 1/2 eqn, but to get their activity, you have to reverse the sign. This means that the more negative (in reduction) is more active.
 

MyLuv

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no.Its in the data sheet(the voltage thing).More active metal mean high ability to be oxidised(eg: Na)
 

toknblackguy

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nope
small shortcut
the standard reduction potential table is essentially the reactivity series!
but as far as knowing whether it will go...i think you just treat it as a cell, and if the Eo of the cell is greater than about 0.1, the reactino will spontaneously occur
 

sneaky pete

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For example:
Zinc in lead nitrate solution
Tin in aluminium sulfate solution


so for his example, since Zinc is higher in the standard reduction potentials sheet (and thus higher in the activity series) than lead, a displacement reaction will occur, zinc and nitrate ions will be in the solution, and solid lead will form?
and for the second one nothing happens since Tin is below aluminum in the SRP sheet?

^is that the correct logic behind answering question such as that?
 
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ND

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I don't have a sheet with me, but i remember that Zn is more active than Pb, so yeh it would displace it. I don't know which is more active between Sn and Al though. If the Sn is more negative on the sheet, then it will displace the Al.
 

toknblackguy

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btw guys...is what i said correct?
cause from memory, i did a trial paper, i think it was james ruse, and there was a trick quetsion - miptiple choice. it asked which of the following displacement reactions would spontaenously occur. now normally, you work throuh a, b, c, and then d. but with like a, the Eo of the cell worked out to be 0.03 or something, whereas the Eo of the cell below it was liek 1.4
so i dunno...
 
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ND

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I just had a look at that Ruse q; the only one that can occur is the displacement of Pb by Sn (B).
 

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