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Plots of log K vs 1/T shows an intercept...

Plots of log K vs `1/T` shows an intercept of shows an intercept of 2 on y-axis with a slop of `45^@` for studied reaction. Which of the following are correct assuming `DeltaH^@ and DeltaS^@` are temperature independent

A

`DeltaS^@ =4.606 cal`

B

`DeltaH^@ =4.606 cal`

C

`DeltaG^@=-2.75 kcal`

D

K=100.8

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The correct Answer is:
To solve the problem, we need to analyze the relationship between the equilibrium constant (K), the Gibbs free energy change (ΔG°), the enthalpy change (ΔH°), and the entropy change (ΔS°) based on the given information about the plot of log K vs. 1/T. ### Step-by-Step Solution: 1. **Understanding the Plot**: The plot of log K vs. 1/T is linear and can be represented by the equation: \[ \log K = -\frac{\Delta H^\circ}{2.303R} \cdot \frac{1}{T} + \frac{\Delta S^\circ}{2.303R} \] Here, the slope of the line is \(-\frac{\Delta H^\circ}{2.303R}\) and the y-intercept is \(\frac{\Delta S^\circ}{2.303R}\). 2. **Extracting Information from the Plot**: - Given that the y-intercept is 2, we can write: \[ \frac{\Delta S^\circ}{2.303R} = 2 \] - Rearranging gives: \[ \Delta S^\circ = 2 \cdot 2.303R \] 3. **Calculating ΔS°**: - The value of R (gas constant) is approximately 2 cal/(mol·K). - Substituting R into the equation: \[ \Delta S^\circ = 2 \cdot 2.303 \cdot 2 = 9.212 \text{ cal/(mol·K)} \] 4. **Using the Slope**: - The slope of the plot is given as 45 degrees. In terms of the slope, we can express it as: \[ \text{slope} = -\frac{\Delta H^\circ}{2.303R} = -1 \quad (\text{since } \tan(45^\circ) = 1) \] - Rearranging gives: \[ \Delta H^\circ = -2.303R \] 5. **Calculating ΔH°**: - Substituting R into the equation: \[ \Delta H^\circ = -2.303 \cdot 2 = -4.606 \text{ cal/mol} \] 6. **Calculating ΔG°**: - The relationship between ΔG°, ΔH°, and ΔS° is given by: \[ \Delta G^\circ = \Delta H^\circ - T\Delta S^\circ \] - Assuming room temperature (T = 298 K): \[ \Delta G^\circ = -4.606 - 298 \cdot 9.212 \] - Calculating this gives: \[ \Delta G^\circ = -4.606 - 2745.576 = -2750.182 \text{ cal/mol} \approx -2.75 \text{ kcal/mol} \] 7. **Finding K**: - Using the relation: \[ \Delta G^\circ = -2.303RT \log K \] - Rearranging gives: \[ \log K = \frac{-\Delta G^\circ}{2.303RT} \] - Substituting the values: \[ \log K = \frac{2750.182}{2.303 \cdot 2 \cdot 298} \] - Calculating gives: \[ K \approx 100.8 \] ### Conclusion: From the calculations, we have: - \(\Delta S^\circ \approx 9.212 \text{ cal/(mol·K)}\) - \(\Delta H^\circ \approx -4.606 \text{ cal/mol}\) - \(\Delta G^\circ \approx -2.75 \text{ kcal/mol}\) - \(K \approx 100.8\) ### Final Answer: The correct options based on the calculations are: - \(\Delta S^\circ = 9.212 \text{ cal/(mol·K)}\) - \(\Delta G^\circ = -2.75 \text{ kcal/mol}\) - \(K \approx 100.8\)

To solve the problem, we need to analyze the relationship between the equilibrium constant (K), the Gibbs free energy change (ΔG°), the enthalpy change (ΔH°), and the entropy change (ΔS°) based on the given information about the plot of log K vs. 1/T. ### Step-by-Step Solution: 1. **Understanding the Plot**: The plot of log K vs. 1/T is linear and can be represented by the equation: \[ \log K = -\frac{\Delta H^\circ}{2.303R} \cdot \frac{1}{T} + \frac{\Delta S^\circ}{2.303R} ...
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