The Question is from neet-chemistry basic-chemistry-concepts concentration-methods, and it was created by the author THIRUPATHI REDDY

Question

An increase in temperature typically causes which of the following changes in a chemical reaction?

THIRUPATHI REDDY · Accepted Answer

## CORE INFORMATION
✓ **Answer**: C
## CONCEPT FRAMEWORK
	**Primary Concept**: Collision Theory and Arrhenius Equation
	**Related Topics**: Reaction Kinetics, Activation Energy, Equilibrium
	**Prerequisites**: Understanding of reaction rates and temperature dependence.
## SOLUTION PATHWAY
**Given Information**:
	Temperature increases.
**Method & Steps**:
	1. **Collision Theory**:  Reaction rates depend on the frequency of successful collisions between reactant molecules.  A successful collision requires sufficient energy (activation energy) and proper orientation.
		Reasoning: Higher temperature means molecules have greater kinetic energy.
	2. **Effect of Temperature**: Increased kinetic energy leads to more frequent collisions and a higher proportion of molecules possessing energy greater than or equal to the activation energy.
		Working:  As temperature increases, the average kinetic energy of molecules increases.
		Key Point:  This results in a higher reaction rate.
	3. **Arrhenius Equation**: The relationship between reaction rate constant ($k$) and temperature (T) is described by the Arrhenius equation: $k = Ae^{-E_a/RT}$, where $A$ is the pre-exponential factor, $E_a$ is the activation energy, $R$ is the gas constant, and $T$ is the absolute temperature.
		Result:  As $T$ increases, the exponential term becomes smaller (less negative), leading to an increase in $k$ and thus the reaction rate.
		Verification:  Experimentally, reaction rates almost always increase with increasing temperature.
 ## OPTION ANALYSIS
[A] :x: Decrease in equilibrium constant:  The effect of temperature on the equilibrium constant depends on the enthalpy change ($\Delta H$) of the reaction. For an exothermic reaction ($\Delta H < 0$), increasing temperature decreases the equilibrium constant. For an endothermic reaction ($\Delta H > 0$), increasing temperature increases the equilibrium constant.  It's not a universal effect like the increase in rate.
[B] :x: Increase in enthalpy change: Enthalpy change ($\Delta H$) is a state function and is independent of the pathway or temperature. It's an intrinsic property of the reaction.
[C] ✓: Increase in reaction rate:  As explained above, increasing temperature directly increases the reaction rate.
[D] :x: Decrease in free energy change:  The change in Gibbs free energy ($\Delta G$) is related to the equilibrium constant ($K$) by $\Delta G = -RT\ln{K}$. The effect of temperature on $\Delta G$ depends on both $\Delta H$ and $\Delta S$ (entropy change).  It's not a universally applicable consequence of increased temperature like the increase in reaction rate.
 ## LEARNING AIDS
	**Common Mistakes**:
		1. Confusing equilibrium constant with reaction rate:  While related, they are different concepts. Temperature affects both, but in different ways.
		2. Forgetting the exponential dependence in the Arrhenius equation:  The relationship between temperature and rate constant is not linear but exponential.
	**Quick Tips**:
		1. Higher temperature = faster reaction (generally).
		2. Think of molecules moving faster and colliding more frequently at higher temperatures.

THIRUPATHI REDDY · Answer

Decrease in equilibrium constant

THIRUPATHI REDDY · Answer

Increase in enthalpy change

THIRUPATHI REDDY · Answer

The correct Option is "Increase in reaction rate"

THIRUPATHI REDDY · Answer

Decrease in free energy change

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