Which of the following conditions may lead to a non-spontaneous change?
a.`DeltaH " and "DeltaS " both "+ve`
b.`DeltaH=-ve,DeltaS=+ve`
c.`DeltaH=+ve,DeltaS=-ve`
d.`DeltaH=-ve,DeltaS=-ve`

Options

A. `DeltaH " and "DeltaS " both "+ve`
B. `DeltaH=-ve,DeltaS=+ve`
C. `DeltaH=+ve,DeltaS=-ve`
D. `DeltaH=-ve,DeltaS=-ve`

Explanation

To determine which conditions may lead to a non-spontaneous change, we need to analyze the Gibbs free energy change (ΔG) using the equation:

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

Where:
- ΔG = change in Gibbs free energy
- ΔH = change in enthalpy
- T = temperature in Kelvin
- ΔS = change in entropy

A reaction is spontaneous if ΔG is less than zero (ΔG < 0) and non-spontaneous if ΔG is greater than zero (ΔG > 0).

### Step-by-Step Solution:

1. **Analyze Option A: ΔH > 0 and ΔS > 0**
- Here, both ΔH and ΔS are positive.
- As temperature (T) increases, the term \(T \Delta S\) also increases.
- Therefore, ΔG can be positive, leading to a non-spontaneous reaction at higher temperatures.

2. **Analyze Option B: ΔH < 0 and ΔS > 0**
- ΔH is negative and ΔS is positive.
- This means that ΔG will be negative at all temperatures because the negative ΔH will outweigh the positive \(T \Delta S\).
- Hence, this condition leads to a spontaneous reaction.

3. **Analyze Option C: ΔH > 0 and ΔS < 0**
- Here, ΔH is positive and ΔS is negative.
- This means ΔG will be positive because both terms contribute to making ΔG positive.
- Thus, this condition leads to a non-spontaneous reaction.

4. **Analyze Option D: ΔH < 0 and ΔS < 0**
- In this case, ΔH is negative and ΔS is negative.
- At low temperatures, the negative ΔH can make ΔG negative, but as temperature increases, the negative \(T \Delta S\) can lead to a positive ΔG.
- Therefore, this condition can also lead to a non-spontaneous reaction at higher temperatures.

### Conclusion:
The conditions that may lead to a non-spontaneous change are:
- Option A: ΔH > 0 and ΔS > 0
- Option C: ΔH > 0 and ΔS < 0
- Option D: ΔH < 0 and ΔS < 0

Thus, the correct options that may lead to a non-spontaneous change are A, C, and D.