Q20E - Organic Chemistry (Mcmurry)

Question

Draw an energy diagram for a one-step reaction with ${\mathbf{K}}_{\mathrm{eq}}\mathbf{<}\mathbf{1}$ . Label the parts of the diagram corresponding to reactants, products, transition state, ${\mathbf{\Delta G}}^o$, and ${\mathbf{\Delta G}}^{\#}$ . Is ${\mathbf{\Delta G}}^o$ positive or negative?

Step-by-Step Solution

Answer

Step 1: Energy profile diagram

An energy profile diagram is a plot of energy against the reaction coordinate.   This shows when the reaction proceeds how the energy of the reactant and product changes.

Step 2: Relation between K eq and exergonic reaction

When ${\text{K}}_{\text{eq}}$ greater than 1 then the energy is out in the reaction which means the reaction is exergonic.

When ${\text{K}}_{\text{eq}}$ less than 1 is then the energy is in the reaction which means the reaction is endergonic.

If ${\text{K}}_{\text{eq}}$< 1 then ${\text{ΔG}}^{\text{o}}$ is positive.

Step 3: Energy profile diagram showing K eq &#160; &#60; &#160; 1

If ${\text{K}}_{\text{eq}}$< 1 then ${\text{ΔG}}^{\text{o}}$ is positive as shown in the following diagram