E deg values (V): Ag+/Ag = 0.80, Fe^3+/Fe^2+ = 0.77, Cu^2+/Cu = 0.34, Fe^2+/Fe = -0.44, Zn^2+/Zn = -0.76, Al^3+/Al = -1.66. Zinc dust is added to a solution containing Ag+, Cu^2+ and Fe^2+, each 1 M. Which statements are correct?

With excess zinc, all three ions Ag+, Cu^2+ and Fe^2+ are reduced to the metals

If zinc is the limiting reagent, the thermodynamically preferred order of reduction is Ag+, then Cu^2+, then Fe^2+

With excess zinc, all three ions Ag+, Cu^2+ and Fe^2+ are reduced to the metals

If zinc is the limiting reagent, the thermodynamically preferred order of reduction is Ag+, then Cu^2+, then Fe^2+

If Fe^3+ were present instead of Fe^2+, zinc would reduce it only to Fe^2+ and not to Fe

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ec046

$E^{\circ}$ values (V): $Ag X^{+} / Ag = 0.80$ , $Fe X^{3 +} / Fe X^{2 +} = 0.77$ , $Cu X^{2 +} / Cu = 0.34$ , $Fe X^{2 +} / Fe = - 0.44$ , $Zn X^{2 +} / Zn = - 0.76$ , $Al X^{3 +} / Al = - 1.66$ . Zinc dust is added to a solution containing $Ag X^{+}$ , $Cu X^{2 +}$ and $Fe X^{2 +}$ , each $1 M$ . Which statements are correct?

AWith excess zinc, all three ions $Ag X^{+}$ , $Cu X^{2 +}$ and $Fe X^{2 +}$ are reduced to the metals
BIf zinc is the limiting reagent, the thermodynamically preferred order of reduction is $Ag X^{+}$ , then $Cu X^{2 +}$ , then $Fe X^{2 +}$
CZinc cannot reduce $Al X^{3 +}$ to Al
DIf $Fe X^{3 +}$ were present instead of $Fe X^{2 +}$ , zinc would reduce it only to $Fe X^{2 +}$ and not to Fe

Zn (

- 0.76 V

) reduces any couple with higher

E^{\circ}

, so

Ag X^{+}

Cu X^{2 +}

and

Fe X^{2 +}

(

- 0.44 > - 0.76

) are all reduced with excess Zn (A). The largest driving force is for the highest

E^{\circ}

, so

Ag X^{+}

is reduced first, then

Cu X^{2 +}

, then

Fe X^{2 +}

(B).

Al X^{3 +} / Al

- 1.66 V

lies below Zn, so Zn cannot reduce it (C). D is wrong: after

Fe X^{3 +}

is reduced to

Fe X^{2 +}

, Zn still has

E^{\circ}

below

- 0.44 V

and reduces

Fe X^{2 +}

to Fe as well.