Question

The lifetimes of transition states are extremely short, so most understandings of transition states were derived from

a) fibre diffraction studies
b) crystallographic studies
c) NMR studies
d) IR studies
e) theoretical studies

Answer 1

Most knowledge of transition states in chemistry, which are high-energy and unstable, is derived from theoretical studies due to their extremely short lifetimes that experimental techniques like NMR cannot easily capture.

Step-by-step explanation:

The understanding of transition states is pivotal in the field of chemistry. Transition states represent a high-energy, unstable state during chemical reactions where reactant molecules quickly proceed to the next steps. Due to their extremely short lifespans, typically around 10-10 seconds, the direct observation of transition states is nearly impossible using experimental techniques such as Nuclear Magnetic Resonance (NMR).

The theoretical studies, often computational, offer a more feasible approach to investigate these fleeting states. These studies rely on quantum mechanical calculations and simulations to predict the behavior and properties of transition states. Theoretical chemistry allows chemists to estimate the potential energy surfaces and to calculate the steric factors, leading to a deeper understanding of chemical kinetics and mechanisms.