Question

Which of the following factors affect the heat of reaction based on Kirchoff equation?

• A. Molecularity
• B. Temperature
• C. Pressure
• D. Volume

Answer 1

The Correct Option is B

The question is about factors affecting the heat of reaction according to the Kirchhoff equation. The Kirchhoff equation is used in thermodynamics to determine how the heat of reaction changes with temperature.

The Kirchhoff equation is given as: 

\(\Delta H(T_2) = \Delta H(T_1) + \int_{T_1}^{T_2} \Delta C_p \, dT\)

Where:

• \(\Delta H(T)\) is the enthalpy change at temperature \(T\).
• \(\Delta C_p\) is the change in heat capacity at constant pressure.
• \(T_1\) and \(T_2\) are the initial and final temperatures, respectively.

The Kirchhoff equation directly indicates a dependence on temperature (\(T_1\) and \(T_2\)). Therefore, the correct factor that affects the heat of reaction according to the Kirchhoff equation is Temperature.

Let's eliminate the other options:

• Molecularity: This refers to the number of molecules or atoms involved in a collision leading to a reaction. It does not affect the heat of reaction in the context of the Kirchhoff equation.
• Pressure: While pressure can affect the volume and hence the physical state changes, it is not directly involved in the Kirchhoff equation for heat changes with temperature.
• Volume: Volume changes could affect pressure but are not directly included in the Kirchhoff equation dependent factors for the enthalpy change with temperature.

Therefore, the correct answer is Temperature.