(i) The order of a reaction can be a fractional number.

(ii) Order of a reaction is experimentally determined quantity.

(iii) The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.

(iv) The order of a reaction is the sum of the powers of the molar concentration of the reactants in the rate law expression.

Correct Answer: (iii) The order of a reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction

Explanation: The order of a reaction is not equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction.