Which of the following statements is correct?
(i) The rate of a reaction decreases with passage of time as the concentration of reactants decreases.
(ii) The rate of a reaction is the same at any time during the reaction.
(iii) The rate of a reaction is independent of temperature change.
(iv) The rate of a reaction decreases with increase in the concentration of the reactant(s).
The answer is the option (i). The rate of a reaction is defined as the change in concentration of the reactant per unit time. Therefore, it is dependent upon the concentration of reactants.