0.2 moles of electrons are possed through three electrolytic cells in series that contain silver ions zinc ions and iron(III) ions
To determine the number of moles of silver ions, zinc ions, and iron(III) ions, we need to know the stoichiometry of the reactions occurring at each electrode.
In the first electrolytic cell, if silver ions are reduced to silver metal, the half-reaction can be written as:
Ag+ + e- -> Ag
Since 0.2 moles of electrons are passed through the cell, this means that 0.2 moles of Ag+ ions are reduced to Ag.
In the second electrolytic cell, if zinc ions are reduced to zinc metal, the half-reaction can be written as:
Zn2+ + 2e- -> Zn
Since 0.2 moles of electrons are passed through the cell, this means that 0.1 moles of Zn2+ ions are reduced to Zn.
In the third electrolytic cell, if iron(III) ions are reduced to iron metal, the half-reaction can be written as:
Fe3+ + 3e- -> Fe
Since 0.2 moles of electrons are passed through the cell, this means that 0.067 moles of Fe3+ ions are reduced to Fe.
Thus, the number of moles of silver ions is 0.2 moles, the number of moles of zinc ions is 0.1 moles, and the number of moles of iron(III) ions is 0.067 moles.