Question

The thermal dissociation of equilibrium of $CaC{O}_3\left(s\right)$ is studied under different conditions.
$CaC{O}_3\left(s\right)\rightleftharpoons CaO\left(s\right)+C{O}_2\left(g\right)$
For this equilibrium, the correct statement(s) is/are
$E_a=$ Activation energy in absence of catalyst
$E_a^{{}^{\prime }}=$ Activation energy in presence of catalyst

• A. $\Delta H$ is dependent on T
• B. K is independent of the initial amount of $CaC{O}_3$
• C. K is dependent on the pressure of $C{O}_2$ at a given T
• D. $\Delta H$ is independent of the catalyst, if any

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A $\Delta H$ is dependent on T
B K is independent of the initial amount of $CaC{O}_3$
C K is dependent on the pressure of $C{O}_2$ at a given T
D $\Delta H$ is independent of the catalyst, if any


$E_a=$ Activation energy in absence of catalyst
$E_a^{{}^{\prime }}=$ Activation energy in presence of catalyst

Heat of reaction is dependent on temperature (Kirchhoff’s equation) in heterogeneous system, equilibrium constant is independent on the molar concentration of solid species.
Heat of reaction is not affected by catalyst. It lowers activation energy.
$CaC{O}_3\left(s\right)\rightleftharpoons CaO\left(s\right)+C{O}_2\left(g\right)$
By Kirchoff's equation
$\Delta H_2^{\circ }\left(at{T}_2\right)=\Delta H_1^{\circ }\left(at{T}_1\right)+\Delta C_p(T_2-T_1)$
$\Delta H^{\circ }$ varies with temperature,
Thus, (a) is correct.
$K=p_{C{O}_2}$
K is dependent on pressure of $C{O}_2$ but independent of molar concentration of $CaC{O}_3$
Thus, (b) and (c) are correct.
At a given temperature, addition of catalysis lowers activation energy. $\Delta H$ remaining constant.
Thus, (d) is also correct.