Identify the element below

Beryllium

Explanation:

Trial Y, because the volume of product formed per unit time is lower than Trial X.

Explanation:

The rate of reaction depends on the amount of reactants present. Now remember that the rate of reaction is either measured as the rate of disappearance of reactants or as the rate of appearance of products.

In this case, we consider the rate of reaction as the rate of appearance of products per unit time. Reading off from the graph, it is quite easy to observe that the volume of product formed per unit time for trial Y is lower than that of Trial X. Since we have earlier agreed that the rate of reaction depends on the initial concentration of reactants. It follows that the reason for the lower volume of product formed per unit time for trial Y is because of a lower initial concentration of the reactants in trial Y. Hence the answer.