Match the items of List I with List II List I List II A. Instantaneou…

The correct answer is Option (4) → A-III, B-IV, C-II, D-I

The rate of a reaction can be expressed over an interval or at an instant, and it is related to concentrations through the rate law.

• (A) Instantaneous rate — This matches (III) short interval of time. It is the rate at one moment, the average rate taken over the smallest time interval (dt → 0).

• (B) Average rate — This matches (IV) long duration of time. It is the change in concentration divided by the time taken, measured over a long interval.

• (C) Mathematical expression for rate of reaction in terms of concentration of reactants — This matches (II) rate law. The rate law (rate equation) expresses the rate in terms of the reactant concentrations.

• (D) Rate of reaction for zero order reaction is equal to — This matches (I) rate constant. Rate = k[R]⁰ = k × 1, so the rate equals the rate constant.

NCERT (2026-27 edition):
Summary – “Chemical kinetics is the study of chemical reactions with respect to reaction rates, effect of various variables, rearrangement of atoms and formation of intermediates. The rate of a reaction is concerned with decrease in concentration of reactants or increase in the concentration of products per unit time. It can be expressed as instantaneous rate at a particular instant of time and average rate over a large interval of time. A number of factors such as temperature, concentration of reactants, catalyst, affect the rate of a reaction. Mathematical representation of rate of a reaction is given by rate law.”

Zero Order Reactions – “Zero order reaction means that the rate of the reaction is proportional to zero power of the concentration of reactants. Consider the reaction, R → P
Rate = −d[R]/dt = k[R]⁰
As any quantity raised to power zero is unity
Rate = −d[R]/dt = k × 1”