PYQ Vault
EbooksTutor

Choose the energy profile of a multistep reaction from the step enthalpies

This type of question, asked 2 times: 2 Apr 2025, 24 Jan 2026 S1. All 2 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    2 Apr 2025

    114
    Reactant A converts to product D through the given mechanism (with the net evolution of heat) : A→BA \rightarrow B slow; ΔH=+ve\Delta H = + ve B→CB \rightarrow C fast; ΔH=−ve\Delta H = - ve C→DC \rightarrow D fast ;ΔH=−ve;\Delta H = - ve Which of the following represents the above reaction mechanism?

    Tap an option to check your answer.

  2. Question 2

    24 Jan 2026 S1

    27
    A→DA \rightarrow D is an endothermic reaction occurring in three steps (elementary). (i) A→BΔHi=+veA \rightarrow B\Delta H_{i}= + ve (ii) B→CΔHii=−veB \rightarrow C\Delta H_{ii}= - ve (iii) C→DΔHiii =−veC \rightarrow D\Delta H_{\text{iii~}}= - ve Which of the following graphs between potential energy ( y -axis) vs reaction coordinate ( x -axis) correctly represents the reaction profile of A→DA \rightarrow D ?

    Tap an option to check your answer.