Answer to Question #149071 in General Chemistry for joseph

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

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

1F of electricity displaces 1 electron from 1 mole of Ag

1F = 1 mole of Ag

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

1F of electricity displaces 1 electron

Therefore to displace the 3 electrons in 1 mole of Al, 3F of electricity is needed.

3F = 1 mole of Al

3F = 27g

yF = 9g

y = 9×3/27 = 1F

Therefore, 1F (97650C) of electricity displaces 9g of Al.