What is the anode and cathode of this problem?
A chemist wishes to determine the concentration of CrO4-2 ions electrochemically. A cell is constructed consisting of saturated calomel electrode (SCE) and a silver wire coated with Ag2CrO4. The SCE is composed of mercury in contact with a saturated solution of calomel (Hg2Cl2). The electrolyte solution in the half-cell is saturated KCl. The E°cell of the SCE half-cell is +0.242 V with respect to the standard hydrogen electrode. The half-reaction for the reduction of Ag2CrO4 is shown below. (15 points)
Ag2CrO4(s) + 2e- 2Ag(s) + CrO4-2(aq) E°cell = 0.446 V
I drew the SCE and AgCr is the wire, KCL is the electrolyte solution. There is Hg in contact with a saturated solution of calomel(HgCl).
I said that Hg2Cl2 acts as the cathode and anode? Is that right.
plz. Answer this question fully.
I said that Hg2Cl2 acted as both the anode and cathode?
In this electrochemical cell setup, the anode and cathode can be determined based on the half-reactions and the direction of electron flow.
First, let's identify the half-reactions:
1. Reduction half-reaction: Ag2CrO4(s) + 2e- → 2Ag(s) + CrO4-2(aq)
2. Oxidation half-reaction: Hg(l) → Hg2+(aq) + 2e-
Now, let's analyze the cell setup:
- The SCE, consisting of mercury in contact with a saturated solution of calomel (Hg2Cl2), serves as a reference electrode and does not take part in the electrochemical reactions. It provides a stable potential to measure the potential difference of the cell.
- The silver wire coated with Ag2CrO4 is likely serving as the cathode since it undergoes reduction, as shown in the reduction half-reaction above.
- The saturated KCl electrolyte solution does not undergo any redox reaction and acts as a bridge, completing the circuit and allowing the flow of ions.
Based on this analysis, the cathode in this setup is the silver wire coated with Ag2CrO4, where reduction occurs. The anode would then be the electrode where oxidation occurs, which is the SCE (the mercury electrode).
To summarize:
- Cathode: Silver wire coated with Ag2CrO4
- Anode: Saturated calomel electrode (SCE) (mercury electrode in contact with Hg2Cl2)
It's important to note that the anode and cathode can sometimes be challenging to distinguish in certain setups. In this case, the reduction half-reaction helps determine the cathode while the remaining electrode becomes the anode. Remember, the cathode is where reduction occurs, and the anode is where oxidation occurs in an electrochemical cell.