The correct mathematical representation of the rate of a reaction is

Rate law equation

The correct answer is Option (4) → Rate law equation

• The rate of a chemical reaction is mathematically expressed using the rate law equation:

$\text{Rate} = k [A]^m [B]^n \dots$

where:

• k = rate constant
• [A], [B] = concentrations of reactants
• m, n = reaction orders with respect to each reactant
• Arrhenius equation relates rate constant k to temperature, not directly the rate.
• Collision frequency and molecularity are related to reaction mechanism, not the general rate expression.