______ in temperature favours an endothermic reaction.

Answer

To answer the question "______ in temperature favours an endothermic reaction," we need to analyze the relationship between temperature and endothermic reactions.

### Step-by-Step Solution:

1. **Understanding Endothermic Reactions**:
- An endothermic reaction is one that absorbs heat from its surroundings. In these reactions, the change in enthalpy (ΔH) is positive.

2. **Equilibrium Constant (Kc)**:
- The equilibrium constant (Kc) for a reaction is affected by temperature. For an endothermic reaction, Kc is related to temperature by the equation:
\[ K_c \propto e^{\frac{-\Delta H}{RT}} \]
- Here, R is the universal gas constant, and T is the temperature in Kelvin.

3. **Effect of Temperature on Kc**:
- Since ΔH is positive for endothermic reactions, increasing the temperature (T) will lead to a decrease in the value of \(-\Delta H/(RT)\).
- As T increases, the exponent becomes less negative, which means \(e^{\frac{-\Delta H}{RT}}\) increases. Therefore, Kc increases.

4. **Conclusion**:
- From the above analysis, we can conclude that an **increase in temperature** favors an endothermic reaction because it results in a higher value of Kc.

### Final Answer:
**Increase in temperature favors an endothermic reaction.**