Question

Threshold energy = Energy of normal molecules + Activation energy.
a.) True
b.) False

Answer 1

Hint: Threshold energy is a certain energy barrier required by molecules to react. Only when molecules have energy higher than this barrier, they react, or the reaction doesn’t occur. As the name suggests, activation energy is the extra energy required by the molecule than its actual energy.

Complete step by step answer:
For any reaction to occur, its individual molecules must collide so as to form a product. Not all molecules taking part in a reaction result in a product. Only those collisions, in which reactant molecules have energy equal to or more than threshold energy, result in products.
The reactant molecules which possess energy equal to or greater than the threshold energy are called activated molecules.
Therefore, activation energy can be defined as the energy in excess to the average energy of the reactant molecules which a molecule must have before colliding with one another, so that their collisions result in products.
Hence,
Activation energy = Threshold energy - Energy of normal molecules.
Threshold energy = Energy of normal molecules + Activation energy.
Therefore, the answer is – option (a) – True.

Additional Information:
The reaction in which the product has a higher energy than the reactant is endothermic, whereas, reaction in which reactant has a higher energy than the product is exothermic.

Note: Catalysts are those compounds, which alters the reaction without actually taking part in it, i.e. they take part in intermediate steps of the reaction, but do not disturb the composition of the reactant or the product. Catalysts function by lowering the activation energy by providing an alternate pathway to a chemical reaction.