A standard hydrogen electrode has zero electrode potential because :

Options

A. hydrogen can be most easily oxidised
B. hydrogen has only one electron
C. the electrode potential is assumed to be zero
D. hydrogen is the lightest element.

Explanation

To answer the question "A standard hydrogen electrode has zero electrode potential because:", we need to analyze the given options and understand the concept of standard hydrogen electrode (SHE) in electrochemistry.

### Step-by-step Solution:

1. **Understanding Standard Hydrogen Electrode (SHE)**:
- The standard hydrogen electrode is a reference electrode that is used to measure the electrode potentials of other half-cells.
- It is defined under standard conditions: a hydrogen ion concentration of 1 M, a hydrogen gas pressure of 1 atm, and a temperature of 298 K (25°C).

2. **Evaluating the Options**:
- **Option A: Hydrogen can be easily oxidized**: While hydrogen can be oxidized, this does not explain why the electrode potential is set to zero.
- **Option B: Hydrogen has only one electron**: The number of electrons does not determine the potential of the electrode; it is more about the reference state.
- **Option C: The electrode potential is assumed to be zero**: This is the correct answer. The standard hydrogen electrode is assigned a potential of 0 V by convention, which serves as a reference point for measuring other electrode potentials.
- **Option D: Hydrogen is the lightest element**: The mass of hydrogen does not influence the electrode potential.

3. **Conclusion**:
- The correct answer is **Option C**: The electrode potential is assumed to be zero. This is a convention used in electrochemistry to provide a standard reference.

### Final Answer:
A standard hydrogen electrode has zero electrode potential because **the electrode potential is assumed to be zero**.

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