Q2 / 90 · KVPY 2010 (SB/SX) · Chemistry
For the reaction $\mathrm{A} \rightarrow \mathrm{B}, \Delta \mathrm{H}^{\circ}=7.5 \mathrm{~mol}^{-1}$ and $\Delta \mathrm{S}^{\circ}=2.5 \mathrm{~J} \mathrm{~mol}^{-1}$. The value of $\Delta \mathrm{G}^{\circ}$ and the temperature at which the reaction reaches equilibrium are, respectively,
- A$0 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $400 \mathrm{~K}$
- B$-2.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $400 \mathrm{~K}$
- C$2.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $200 \mathrm{~K}$
- Correct answerD$0 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $300 \mathrm{~K}$
Solution
At equation $\Delta \mathrm{G}^{\circ}=0$
$$
\therefore \mathrm{T}=\frac{\Delta \mathrm{H}}{\Delta \mathrm{S}}=\frac{7.5 \times 1000}{25}=300 \mathrm{~K}
$$
Hence, the correct answer is option: 'D'.