Question

For a chemical reaction

A → B

The threshold energy of reaction is 50 K.J/mol. The average internal energy of A is 25 K.J/mol. The activation energy of A is:

Options

A
25 K.J/mol
B
50 K.J/mol
C
100 K.J/mol
D
125 K.J/mol
E
0 K.J/mol

Explanation

The activation energy for a chemical reaction is the minimum energy required to convert the reactants into products. It is calculated by subtracting the average internal energy of the reactants from the threshold energy. In this case, Activation energy = Threshold energy - Internal energy = 50 K.J/mol - 25 K.J/mol = 25 K.J/mol. This means option A is correct. Options B, C, and D are incorrect as they do not accurately reflect the relationship between threshold and internal energies. Option E is incorrect because it suggests no energy barrier, which is not the case here.

This is the correct calculation: Activation energy = Threshold energy - Internal energy = 50 K.J/mol - 25 K.J/mol = 25 K.J/mol.

This value represents the threshold energy, not the activation energy.

This value is incorrect and does not relate to any given data in the question.

This is an incorrect value, and there is no calculation from the given data that would result in this value.

This would imply no energy barrier, which contradicts the presence of a threshold energy.