1)

Which of the following lines correctly show the temperature dependance of equilibrium constant  K, for an exothermic reaction?

4820197_equli.JPG

 


A) A and B

B) B and C

C) C and D

D) A and D

Answer:

Option A

Explanation:

From thermodynamics,

$ln k=\frac{-\triangle H^{o}}{RT}+\frac{\triangle S^{o}}{R}$     ......(i)

Mathematically, the equation of straight line is

  $y-c+mx$    .....(ii)

After comparing Eq. (ii) with (i) we get,

slope= $\frac{\triangle H^{o}}{R}$ and intercept= $\frac{\triangle S^{o}}{R}$

Now, we know for exothermic reaction $\triangle H$ is negative(-)ve. But here,

Slope = $\frac{\triangle H^{o}}{R}$ is postive

So, lines A and B in the graph represent temperature dependence of equilibrium constant K for an exothermic reaction as shown below

482019900_line12.jpg