The reaction: A + 3 B = D + F was studied and the following mechanism was finally determined
A + B = C (fast)
C + B = D + E (slow)
E + B = F (very fast)
The step with largest activation energy is
a. the first step
b. the second step
c. the third step
d. none of the steps has an activation energy
e. all of the steps have the same activation energy
?
The one with the largest activation energy will be the slowest because it takes more energy to get over the hump.
To determine which step in the reaction has the largest activation energy, we need to compare the activation energies of each step in the mechanism provided.
Activation energy is the minimum energy required for a chemical reaction to occur. It is usually denoted as Ea.
Let's assign Ea1, Ea2, and Ea3 to represent the activation energies for the first, second, and third steps, respectively.
From the given mechanism:
Step 1: A + B -> C (fast)
Step 2: C + B -> D + E (slow)
Step 3: E + B -> F (very fast)
To compare the activation energies, we can consider the rate-determining step. The rate-determining step is the slowest step in the reaction that determines the overall reaction rate.
In this case, the second step (C + B -> D + E) is labeled as "slow," indicating that it is the rate-determining step. Therefore, we can conclude that this step has the largest activation energy among the three steps.
Therefore, the correct answer is:
b. The second step has the largest activation energy.
The step with the largest activation energy can be determined by looking at the rate-determining step, which is the slowest step in the mechanism. In this case, the second step (C + B = D + E) is the slowest step. Therefore, the correct answer is:
b. the second step