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Hi, can someone please help me with this question?
I've always thought that ANIONS migrate to the ANODE (regardless if it's a galvanic or electrolytic cell)...
However, in this Free Standing Question in Kaplan Exam 6, the answer choice states that Anions migrate to the Cathode. Is this an error? Or am I incorrect in my understanding? Thank you so much
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QUESTION (I picked A)
77. In a galvanic cell, which of the following statements is true?
A. Anions migrate toward the anode, and electrons flow from the anode to the cathode.
B. Anions migrate toward the anode, and electrons flow from the cathode to the anode.
C. Anions migrate toward the cathode, and electrons flow from the anode to the cathode.
D. Anions migrate toward the cathode, and electrons flow from the cathode to the anode.
ANSWER Stated by Kaplan
77. C
This type of question cannot be answered by prediction – we must read through the answer
choices until we find a true statement. Scanning through the answer choices, we can quickly see
that they are all statements regarding the directional flow of anions and electrons in galvanic
cells. Now, recall that galvanic cells are spontaneous electrochemical cells. That is, in a galvanic
cell a spontaneous chemical reaction is used to generate an electric current. In all electrochemical
cells, electrons will flow from the anode to cathode. Therefore we can eliminate choices B
and D. Now, we must determine the direction of anion movement in a spontaneous versus a nonspontaneous
electrochemical cell. In all electrochemical cells, oxidation will occur at the anode
(mnemonic: AN OX), and reduction will occur at the cathode (RED CAT). In a spontaneous cell,
the anode will be negative since the electrochemical potential of the cell drives electrons to be
move from anode to cathode. Since positive charges attract negative charges and vice versa,
cations (positive always) will move toward the anode (negative in a galvanic cell), and anions
(negative always) will move toward the cathode (positive in a galvanic cell). Choice C is therefore
correct.
I've always thought that ANIONS migrate to the ANODE (regardless if it's a galvanic or electrolytic cell)...
However, in this Free Standing Question in Kaplan Exam 6, the answer choice states that Anions migrate to the Cathode. Is this an error? Or am I incorrect in my understanding? Thank you so much
---
QUESTION (I picked A)
77. In a galvanic cell, which of the following statements is true?
A. Anions migrate toward the anode, and electrons flow from the anode to the cathode.
B. Anions migrate toward the anode, and electrons flow from the cathode to the anode.
C. Anions migrate toward the cathode, and electrons flow from the anode to the cathode.
D. Anions migrate toward the cathode, and electrons flow from the cathode to the anode.
ANSWER Stated by Kaplan
77. C
This type of question cannot be answered by prediction – we must read through the answer
choices until we find a true statement. Scanning through the answer choices, we can quickly see
that they are all statements regarding the directional flow of anions and electrons in galvanic
cells. Now, recall that galvanic cells are spontaneous electrochemical cells. That is, in a galvanic
cell a spontaneous chemical reaction is used to generate an electric current. In all electrochemical
cells, electrons will flow from the anode to cathode. Therefore we can eliminate choices B
and D. Now, we must determine the direction of anion movement in a spontaneous versus a nonspontaneous
electrochemical cell. In all electrochemical cells, oxidation will occur at the anode
(mnemonic: AN OX), and reduction will occur at the cathode (RED CAT). In a spontaneous cell,
the anode will be negative since the electrochemical potential of the cell drives electrons to be
move from anode to cathode. Since positive charges attract negative charges and vice versa,
cations (positive always) will move toward the anode (negative in a galvanic cell), and anions
(negative always) will move toward the cathode (positive in a galvanic cell). Choice C is therefore
correct.
