Thermodynamics and Thermochemistry 1 Question 66
69. When 1-pentyne $(A)$ is treated with $4 \mathrm{~N}$ alcoholic $\mathrm{KOH}$ at $175^{\circ} \mathrm{C}$, it is converted slowly into an equilibrium mixture of $1.3 %$ 1-pentyne $(A), 95.2 % \quad 2$-pentyne $(B)$ and $3.5 %$ of 1, 2-pentadiene $(C)$. The equilibrium was maintained at $175^{\circ} \mathrm{C}$. Calculate $\Delta G^{\circ}$ for the following equilibria.
$$ \begin{array}{lll} B \rightleftharpoons A, & \Delta G^{\circ}{ }{1}=\text { ? } \ B \rightleftharpoons C, & \Delta G^{\circ}{ }{2}=\text { ? } \end{array} $$
From the calculated value of $\Delta G^{\circ}{ }{1}$ and $\Delta G^{\circ}{ }{2}$ indicate the order of stability of $(A),(B)$ and $(C)$. Write a reasonable reaction mechanism showing all intermediates leading to $(A),(B)$ and $(C)$.
(2001, 10M)
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Solution:
- At equilibrium : $B \rightleftharpoons A$
$$ \begin{array}{cc}
