In an experiment setup for the measurement of `EMF` of a half cell using a reference electrode and a salt bridge, when the salt bridge is removes, the voltage

Options

A. Does not change
B. Increase to maximum
C. Decreases to half the value
D. Drops to zero

Explanation

To solve the question regarding the effect on the voltage when the salt bridge is removed from an electrochemical cell setup, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- In an electrochemical cell, we have two half-cells: one is a reference electrode (like a standard hydrogen electrode) and the other is the half-cell whose EMF (electromotive force) we want to measure.
- The salt bridge connects these two half-cells and allows for the flow of ions, which is essential for maintaining electrical neutrality.

**Hint**: Remember that the salt bridge is crucial for the functioning of the electrochemical cell.

2. **Role of the Salt Bridge**:
- The primary function of the salt bridge is to maintain electrical neutrality in both half-cells by allowing the flow of ions. It also completes the circuit, enabling the flow of electrons between the electrodes.

**Hint**: Think about what happens to the flow of ions and electrons if the salt bridge is removed.

3. **Removing the Salt Bridge**:
- When the salt bridge is removed, the connection between the two electrodes is broken. This means that ions can no longer move between the half-cells, which disrupts the balance of charge.
- As a result, the flow of electrons is also halted because there is no complete circuit for the electrons to travel through.

**Hint**: Consider what happens to the electrical circuit when a critical component is removed.

4. **Effect on Voltage**:
- Since the flow of electrons is essential for generating a measurable voltage (EMF), the removal of the salt bridge means that the circuit is effectively broken.
- Consequently, the voltmeter connected to the circuit will show a reading of zero volts because there is no current flowing through the circuit.

**Hint**: Recall that a complete circuit is necessary for any voltage to be measured.

5. **Conclusion**:
- Therefore, when the salt bridge is removed, the voltage drops to zero. The correct answer to the question is that the voltage will drop to zero.

**Hint**: Always check the implications of breaking a circuit in electrochemical systems.

### Final Answer:
When the salt bridge is removed, the voltage drops to zero.