In a spontaneous process the system undergoes

Options

A. No energy change
B. Lowering of free energy
C. Lowering of entropy of universe
D. Increase in internal energy always

Answer

To solve the question regarding spontaneous processes in thermodynamics, we need to analyze the options provided based on the principles of thermodynamics, particularly focusing on Gibbs free energy (ΔG) and entropy (ΔS).

### Step-by-Step Solution:

1. **Understanding Spontaneous Processes**:
- A spontaneous process is one that occurs without the need for external energy. It is driven by the natural tendency of systems to move toward a state of lower free energy.

2. **Gibbs Free Energy (ΔG)**:
- The spontaneity of a process can be determined using the Gibbs free energy change equation:
\[ \Delta G = \Delta H - T \Delta S \]
- Where:
- ΔG = change in Gibbs free energy
- ΔH = change in enthalpy
- T = absolute temperature
- ΔS = change in entropy

3. **Condition for Spontaneity**:
- For a process to be spontaneous, ΔG must be negative (ΔG < 0).

4. **Analyzing the Options**:
- **Option A: No energy change**:
- This is incorrect because spontaneous processes involve energy changes. Therefore, this option does not hold true.

- **Option B: Lowering of free energy**:
- This is correct. A spontaneous process is characterized by a decrease in Gibbs free energy (ΔG < 0).

- **Option C: Lowering of entropy of the universe**:
- This is incorrect. For a spontaneous process, the total entropy of the universe (system + surroundings) must increase (ΔS_universe > 0).

- **Option D: Increasing internal energy always**:
- This is also incorrect. There is no direct relationship between spontaneous processes and an increase in internal energy. Internal energy can change in various ways depending on the process.

5. **Conclusion**:
- The correct answer is **Option B: Lowering of free energy**.