At the molecular level, the study of chemical kinetics deals with

The correct answer is Option (1) → reaction mechanisms involving the orientation and energy of molecules undergoing collisions

Chemical kinetics is studied at two levels. At the macroscopic level we look at quantities that can be measured in bulk. At the molecular level we look at how the molecules themselves react: the mechanism, and the orientation and energy of the molecules when they collide.

Why the other options are incorrect

Option (2) the amounts of reactants reacted and of products formed — Incorrect. This is the interest at the macroscopic level.

Option (3) the rates of consumption of reactants and of formation of products — Incorrect. These rates are also studied at the macroscopic level.

Option (4) the extent to which a reaction will proceed — Incorrect. The extent of a reaction is found from chemical equilibrium, not from a study of collisions.

NCERT (2026-27 edition):
Chemical Kinetics (introduction) – “At the macroscopic level, we are interested in amounts reacted or formed and the rates of their consumption or formation. At the molecular level, the reaction mechanisms involving orientation and energy of molecules undergoing collisions, are discussed.”