The incorrect expression among the following is

Options

A. `(DeltaG_("system"))/(DeltaS_("Total")) =-T`
B. In isothermal process, `W_("reversible") = -nRT` ln `(V_(t))/(V_(i))`
C. `ln K=(DeltaH^(@) - TDeltaS^(@))/(RT)`
D. `K = e^(-DeltaG^(@)//RT)`

Explanation

To determine the incorrect expression among the given options, we will analyze each expression step by step.

### Given Expressions:
1. **Option A**: \(\frac{\Delta G}{\text{system}} + \Delta S_{\text{total}} = -2 - T\)
2. **Option B**: \(W_{\text{reversible}} = -nRT \ln \frac{V_{th}}{V_i}\)
3. **Option C**: \(RT \ln K = \Delta H^0 - T \Delta S^0\)
4. **Option D**: \(\ln K = -\frac{\Delta G^0}{RT}\)

### Step-by-Step Analysis:

#### Step 1: Analyze Option A
- The expression states: \(\frac{\Delta G}{\text{system}} + \Delta S_{\text{total}} = -2 - T\).
- Rearranging gives us \(\Delta G = -2 - T - \Delta S_{\text{total}}\).
- According to the Gibbs free energy equation, \(\Delta G = \Delta H - T \Delta S\).
- This expression does not directly correspond to a standard thermodynamic equation, but it can be valid under specific conditions.
- **Conclusion**: This expression may not be incorrect outright, but we need to check others.

#### Step 2: Analyze Option B
- The expression states: \(W_{\text{reversible}} = -nRT \ln \frac{V_{th}}{V_i}\).
- This is a known formula for work done during a reversible isothermal expansion or compression.
- **Conclusion**: This expression is correct.

#### Step 3: Analyze Option C
- The expression states: \(RT \ln K = \Delta H^0 - T \Delta S^0\).
- Rearranging gives us \(\Delta H^0 = RT \ln K + T \Delta S^0\).
- The correct relationship from thermodynamics is \(\Delta G^0 = \Delta H^0 - T \Delta S^0\) and also \(\Delta G^0 = -RT \ln K\).
- Therefore, if we substitute \(\Delta G^0\) into the equation, we see that this expression is incorrect because it does not match the standard form.
- **Conclusion**: This expression is incorrect.

#### Step 4: Analyze Option D
- The expression states: \(\ln K = -\frac{\Delta G^0}{RT}\).
- This is a correct expression derived from the relationship between Gibbs free energy and equilibrium constant.
- **Conclusion**: This expression is correct.

### Final Conclusion:
The incorrect expression among the options is **Option C**: \(RT \ln K = \Delta H^0 - T \Delta S^0\).