Question
Question: (١٢) من جهود الأقطاب الذي: $X^{2+} + 2e^{-} \longrightarrow X \quad , E^{\circ} = -0.41 V$ $Y \lon...
(١٢) من جهود الأقطاب الذي:
X2++2e−⟶X,E∘=−0.41V
Y⟶Y2++2e−,E∘=−0.23V
أي الاختيارات التالية يمثل التفاعل التالي؟
X+Y2+⟶X2++Y

غير تلقائي ، وكتلة القطب (X) تقل.
غير تلقائي ، وكتلة القطب (Y) تقل.
تلقائي ، وكتلة القطب (X) تقل.
تلقائي ، وكتلة القطب (Y) تقل.
تلقائي ، وكتلة القطب (X) تقل.
Solution
The problem asks us to determine the spontaneity of a given redox reaction and the change in mass of the electrodes, based on the provided standard electrode potentials.
1. Identify the half-reactions and their standard potentials: We are given:
- Reduction of X: X2++2e−⟶X,EX2+/X∘=−0.41V (This is the standard reduction potential for X).
- Oxidation of Y: Y⟶Y2++2e−,EY/Y2+∘=−0.23V (This is the standard oxidation potential for Y).
2. Analyze the target reaction: The reaction to be analyzed is: X+Y2+⟶X2++Y
Let's break this down into oxidation and reduction half-reactions:
- Oxidation half-reaction: X⟶X2++2e−
- Reduction half-reaction: Y2++2e−⟶Y
3. Determine the standard potentials for the half-reactions in the target reaction:
- For the oxidation of X (X⟶X2++2e−): The standard oxidation potential is the negative of the standard reduction potential. Eox∘(X/X2+)=−Ered∘(X2+/X)=−(−0.41V)=+0.41V.
- For the reduction of Y (Y2++2e−⟶Y): The standard reduction potential is the negative of the standard oxidation potential given for Y. Ered∘(Y2+/Y)=−Eox∘(Y/Y2+)=−(−0.23V)=+0.23V.
4. Calculate the standard cell potential (Ecell∘): The standard cell potential is the sum of the standard oxidation potential and the standard reduction potential for the reaction. Ecell∘=Eoxidation∘+Ereduction∘ Ecell∘=Eox∘(X/X2+)+Ered∘(Y2+/Y) Ecell∘=(+0.41V)+(+0.23V) Ecell∘=+0.64V
5. Determine the spontaneity of the reaction: Since Ecell∘ is positive (+0.64V>0), the reaction is spontaneous.
6. Analyze the mass change of the electrodes:
- Oxidation of X: X⟶X2++2e− In this process, solid X is converted into X2+ ions in the solution. This means the mass of the solid X electrode will decrease.
- Reduction of Y: Y2++2e−⟶Y In this process, Y2+ ions from the solution are deposited as solid Y. This means the mass of the solid Y electrode will increase.
Therefore, the correct statement is that the reaction is spontaneous, and the mass of electrode X decreases.