Answer:
lower than the atmospheric pressure
Explanation:
An eudiometer have a graduated glass tube , where the mixture of the gases react with the electric spark , which helps to measure the change in the volume of the gases , during the process of the chemical reaction .
From the question ,
when the water level in the eudiometer is below that in the cylinder , then , the pressure in the eudiometer will be lower than the pressure of the atmosphere .
A chemical reaction occurs only when the collision between the reacting molecules takes place. However, not all the collisions are efficient in making the reaction. The products are produced only when the molecules colliding exhibits a certain kind of minimum energy known as threshold energy.
The threshold energy refers to the least amount of energy needed for the reactants to collide effectively, and to produce the activated complex. It is kinetic energy in supplementation with the energy of activation. Hence, threshold energy is more in comparison to the activation energy.