CUET Preparation Today
Which of the following statements is correct? |
1 and 2 1 and 3 1, 2 and 3 2 and 3 |
1 and 2 |
The correct answer is option (1) - 1 and 2 (1) Order of a reaction can be known from experimental results and not from the stoichiometry of a reaction. The order of a reaction is determined by experimental results, not by the stoichiometry of the reaction. This is because the order of a reaction is defined as the sum of the powers of the concentrations of the reactants in the rate equation, which is determined experimentally. Therefore, statement (1) is correct. (2) Molecularity of a reaction refers to (i) each of the elementary steps in (an overall mechanism of) a complex reaction or (ii) a single-step reaction. The molecularity of a reaction refers to the number of molecules involved in an elementary (single-step) reaction. It can refer to each of the elementary steps in a complex reaction or a single step reaction. Therefore, statement (2) is correct. Hence, statements 1 and 2 are correct. Let us see why statement 3 is false. The overall order of a reaction is not necessarily the sum of the stoichiometric coefficients of the reactants in the balanced equation. Instead, it is the sum of the individual reaction orders with respect to each reactant. These reaction orders can be determined experimentally and may not necessarily match the stoichiometric coefficients. For example, the reaction \(A^m + B^n \longrightarrow AB_x\) could have an overall order that is different from \(m + n\) if the reaction rate is not solely determined by the concentrations of \(A\) and \(B\). Each reactant's concentration can have a different impact on the rate of the reaction, as determined by their respective reaction orders. |
