Consider the conversion of oxygen to ozone: $3\mathrm{O}_{2(g)} \rightleftharpoons 2\mathrm{O}_{3(g)

Question

Consider the conversion of oxygen to ozone: $3\mathrm{O}_{2(g)} \rightleftharpoons 2\mathrm{O}_{3(g)}$. This process requires an electric discharge and results in a highly unstable product. The signs of $\Delta H$, $\Delta S$, and $\Delta G$ for this forward reaction are respectively

Professor PC Thomas Classes · Answer

(a) : The formation of ozone from oxygen is an endothermic process because it requires a continuous supply of energy (electric discharge), so $\Delta H$ is positive. The reaction involves 3 moles of gaseous reactants combining to form 2 moles of gaseous products, reducing randomness, meaning $\Delta S$ is negative. Because it forms a highly unstable product and requires external energy to proceed, it is non-spontaneous under standard conditions, so $\Delta G$ is positive.