Question

which of the following is true for diffusion controlled reactions? a)the time required to break or form bonds is much more than the time required for the reactants to diffuse such that they are proximal to one another in the solution. b)the energy barrier associated with breaking or forming bonds is much higher than the barrier associated with the diffusion of the reactants to form the caged complex in the solution. c)enzymes, at their initial stages of evolution toward a particular substrate, tend to operate at the diffusion limit. d)the rate of bond forming/breaking is much faster than rate required for a caged complex to separate.

Answer 1

The true statement for diffusion-controlled reactions is that enzymes at their initial evolutionary stages towards a substrate tend to operate at the diffusion limit, as their rate constants approach this natural speed limit for reactions.

Step-by-step explanation:

The statement that is true for diffusion-controlled reactions is: c) enzymes, at their initial stages of evolution toward a particular substrate, tend to operate at the diffusion limit. This is because the rate-limiting step in such reactions is the diffusion process that brings reactants together into close proximity. Once enzymes evolve sufficiently to catalyze a specific reaction effectively, their rate constants approach the diffusion limit, which serves as nature's speed limit for reactions.

The other statements a), b) and d), do not correctly describe diffusion-controlled reactions as they either overestimate the time required for bond formation or breaking, or they incorrectly describe the energy barriers in relation to diffusion.