Which of the following can be zero for isothermal reversible expansion?

Options

A. `Delta E`
B. `Delta H`
C. `Delta T`
D. All of these

Answer

To solve the question regarding which of the following can be zero for isothermal reversible expansion, we will consider the thermodynamic properties involved in such a process.

### Step-by-Step Solution:

1. **Understanding Isothermal Reversible Expansion**:
- In an isothermal process, the temperature (T) remains constant.
- For a reversible process, the system is in equilibrium with its surroundings at all times.

2. **Change in Internal Energy (ΔE)**:
- The change in internal energy (ΔE) for an ideal gas is given by the equation:
\[ \Delta E = nC_V\Delta T \]
- Since the process is isothermal, ΔT = 0. Therefore, ΔE = 0.

3. **Change in Enthalpy (ΔH)**:
- The change in enthalpy (ΔH) is given by:
\[ \Delta H = \Delta E + \Delta (PV) \]
- For an ideal gas under isothermal conditions, the change in enthalpy can also be shown to be zero because the internal energy change is zero and the work done is balanced by heat exchange. Thus, ΔH = 0.

4. **Change in Temperature (ΔT)**:
- Since the process is isothermal, the temperature does not change. Therefore, ΔT = 0.

5. **Conclusion**:
- From the analysis above, we can conclude that for isothermal reversible expansion:
- ΔE = 0
- ΔH = 0
- ΔT = 0
- Hence, all the options provided in the question can be zero.

6. **Final Answer**:
- Therefore, the correct option is (d) All of these are 0.