Answer to Question #149251 in General Chemistry for Ryan

Question

If x electron are need to displace 108g silver from a solution which contains ag+ ions, how many electrons are needed to displace 9g of aluminum from a solution which contains Al3+ ion?
( Al=27 ,Ag=108)

Answer 1

$Ag \to Ag^+ + e^-$

$Al \to Al^{3+} + 3e^-$

108g of Ag = 1 mole

9g of Al = 1/3 mole

1 mole of electrons is needed to reduce 1 mole of Ag

3 moles of electrons are needed to reduce 1 mole of Al

Therefore 1 mole of electrons is needed to reduce 1/3 moles of Al

So to answer to the question, if x moles of electrons are needed to reduce 108g of silver, x moles of electrons are also needed to reduce 9g of Aluminium.