Assertion: The rate of a reaction depends on the concentration of reactants(s) according to the rate law expression determined experimentally.
Reason: The rate of reaction decreases as the reaction moves in the forward direction because the concentration of reactant(s) decreases.
Answer & explanation
Correct answer: option 1
For any reaction, A → B
r = k [A]x
where x is the order of a reaction.
As the reaction will proceed, rate of reaction decreases because concentration of reactant decreases as more product will be formed.