Explain how the half-cells are kept electrically neutral in a voltaic cell with a copper nitrate solution on the left and a silver nitrate solution on the right.
With a salt bridge between the two solutions.
In a voltaic cell, half-cells are used to house the different redox reactions that occur during the cell's operation. To keep each half-cell electrically neutral, several measures are taken in a voltaic cell with a copper nitrate solution on the left and a silver nitrate solution on the right:
1. Copper Nitrate Solution Half-Cell:
a. Copper ions (Cu2+) are present in the copper nitrate solution. These ions are responsible for the redox reaction occurring in the copper half-cell.
b. To maintain electrical neutrality in this half-cell, anions (NO3-) are also present in the copper nitrate solution. These anions balance the positive charge of the copper ions.
2. Silver Nitrate Solution Half-Cell:
a. Silver ions (Ag+) are present in the silver nitrate solution. These ions are involved in the redox reaction occurring in the silver half-cell.
b. Like in the copper half-cell, anions (NO3-) are present in the silver nitrate solution to maintain electrical neutrality. These anions balance the positive charge of the silver ions.
3. Salt Bridge:
a. A salt bridge is typically placed between the two half-cells to complete the circuit and maintain electrical neutrality in each half-cell.
b. The salt bridge contains an electrolyte solution, usually consisting of an inert salt, such as potassium nitrate (KNO3). This electrolyte allows ions to flow and maintain electrical neutrality by balancing charge between the half-cells.
c. In the case of the copper nitrate and silver nitrate solutions, the salt bridge allows anions (NO3-) to flow from the copper half-cell to the silver half-cell, completing any charge imbalances.
By having copper ions and anions in the copper nitrate solution and silver ions and anions in the silver nitrate solution, along with the salt bridge, the electrical neutrality of each half-cell is maintained in the voltaic cell.
In a voltaic cell, half-cells play a crucial role in generating electrical energy. Each half-cell consists of an electrode and an electrolyte solution. In this case, we have a copper nitrate solution on the left (the left half-cell) and a silver nitrate solution on the right (the right half-cell).
To keep the half-cells electrically neutral, two main factors come into play: the movement of ions and the electron transfer between the electrodes.
First, let's focus on the copper nitrate solution. When copper nitrate, Cu(NO3)2, dissolves in water, it dissociates into Cu2+ and NO3- ions. These ions are responsible for maintaining electrical neutrality within this half-cell. Copper (Cu) metal serves as an electrode, and Cu2+ ions migrate towards the electrode, balancing the positive charge of the metal. On the other hand, NO3- anions remain in the solution, ensuring electrical neutrality within that half-cell.
Now, let's turn our attention to the silver nitrate solution. Similar to copper nitrate, when silver nitrate, AgNO3, dissolves in water, it dissociates into Ag+ and NO3- ions. In this half-cell, silver (Ag) metal acts as the electrode, attracting Ag+ ions towards it to balance the positive charge. The NO3- anions remain in the solution to maintain electrical neutrality within this half-cell.
In summary, the key point to achieve electrical neutrality in each half-cell is the movement of ions. Positively charged metal ions from the electrolyte solution migrate towards the electrode, while negatively charged anions remain in the solution. This separation of positively and negatively charged species ensures that each half-cell remains electrically neutral.