The standard electrode potential for the reduction of Eu3+(aq) to Eu2+(aq) is −0.43 V. determine which of the following is capable of reducing Eu3+(aq) to Eu2+(aq) under standard-state conditions?

(a) Sn2+(aq)
(b) ln(s)
(c) HCN(aq)
(d) La(s)

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Eu^3+ + e ==> Eu^2+
Sn^2+ ==> Sn^4+ + 2e
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You have Eo for Eu3+ to Eu^2+.
Look up Sn^4+ to Sn^2+, change the sign, and add to the Eu couple. If the resulting E value is + that material (Sn2+ in this case) will reduce the Eu 3+ to 2+. If negative, no.
b,c,d, are done the same way.

Yes

thanks you

To determine which of the substances is capable of reducing Eu3+(aq) to Eu2+(aq) under standard-state conditions, we need to compare the standard electrode potentials of these substances with the standard electrode potential of Eu3+/Eu2+.

The standard electrode potential of Eu3+/Eu2+ is -0.43 V. Any substance with a more negative standard electrode potential can reduce Eu3+(aq) to Eu2+(aq).

Let's compare the standard electrode potentials of the given substances:

(a) Sn2+(aq): The standard electrode potential for Sn2+(aq)/Sn is -0.14 V, which is less negative than -0.43 V. Therefore, Sn2+(aq) cannot reduce Eu3+(aq) to Eu2+(aq).

(b) ln(s): The standard electrode potential for ln(s)/ln(aq) is not readily available. Therefore, we cannot determine if ln(s) can reduce Eu3+(aq) to Eu2+(aq) based on the given information.

(c) HCN(aq): HCN(aq) is not a redox active substance and cannot act as a reducing agent. Therefore, it cannot reduce Eu3+(aq) to Eu2+(aq).

(d) La(s): The standard electrode potential for La3+(aq)/La is -2.371 V, which is more negative than -0.43 V. Therefore, La(s) can reduce Eu3+(aq) to Eu2+(aq).

Based on the comparison of standard electrode potentials, the substance capable of reducing Eu3+(aq) to Eu2+(aq) under standard-state conditions is (d) La(s).