A chemical reaction is spontaneous at `298 K` but non spontaneous
at `350 K` . Which one of the following is true
for the reaction ?

Options

A. `{:(DeltaG,DeltaH,DeltaS),(-,+,+):}`
B. `{:(DeltaG,DeltaH,DeltaS),(+,+,+):}`
C. `{:(DeltaG,DeltaH,DeltaS),(-,+,-):}`
D. `{:(DeltaG,DeltaH,DeltaS),(-,-,-):}`

Explanation

To solve the problem, we need to analyze the relationship between Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) at different temperatures. The key equation we will use is:

\[ \Delta G = \Delta H - T \Delta S \]

### Step-by-Step Solution:

1. **Understanding Spontaneity**:
- A reaction is spontaneous when ΔG < 0.
- A reaction is non-spontaneous when ΔG > 0.

2. **Given Conditions**:
- The reaction is spontaneous at 298 K: ΔG < 0.
- The reaction is non-spontaneous at 350 K: ΔG > 0.

3. **Analyzing the Change in ΔG**:
- As the temperature increases from 298 K to 350 K, ΔG changes from negative to positive. This indicates that the relationship between ΔH and ΔS must change with temperature.

4. **Using the Gibbs Free Energy Equation**:
- At 298 K, since ΔG < 0, we can write:
\[ \Delta H - (298 \Delta S) < 0 \quad \Rightarrow \quad \Delta H < 298 \Delta S \]
- At 350 K, since ΔG > 0, we can write:
\[ \Delta H - (350 \Delta S) > 0 \quad \Rightarrow \quad \Delta H > 350 \Delta S \]

5. **Combining the Inequalities**:
- From the first inequality, we have:
\[ \Delta H < 298 \Delta S \]
- From the second inequality, we have:
\[ \Delta H > 350 \Delta S \]
- This means that as the temperature increases, the term \(T \Delta S\) must become larger than ΔH, leading to the conclusion that ΔS must be negative for the reaction to switch from spontaneous to non-spontaneous.

6. **Conclusion**:
- For the reaction to be spontaneous at lower temperatures and non-spontaneous at higher temperatures, both ΔH and ΔS must be negative. Thus, the correct answer is that both ΔH and ΔS are negative.

### Final Answer:
The correct combination for the reaction is that both ΔH and ΔS are negative.