Q. 10 P - Organic Chemistry (Mcmurry)

Question

Which reaction is more energetically favored, one with ${\mathbf{\Delta G}}^{\mathbf{o}}$ = - 44 or one with ${\mathbf{\Delta G}}^{\mathbf{o}}$= +44 ?

Step-by-Step Solution

Answer

The reaction with ${\mathbf{\Delta G}}^{\mathbf{o}}$= - 44 is energetically more favorable.

Step 1: Spontaneous reaction

Reactions that proceed without an external energy supply are called a spontaneous reaction.

For a reaction to be spontaneous, it needs to have  a negative value of Gibbs free energy.

Also,for the reaction to be spontaneous, the value of ${\mathrm{\Delta S}}^{\mathrm{o}}$ needs to be positive.

Step 2: Energetically favored reaction

The reaction with a negative ${\mathrm{\Delta G}}^{\mathrm{o}}$ value is energetically favorable. In the above two cases, one value is positive and the other is negative. So the negative value of Gibbs free energy indicates that the reaction is energetically favored.

Hence, the reaction with   $\Delta G^{\mathrm{o}}$= - 44  is energetically more favorable.