Question

Equilibrium constant $K_p$ for following reaction : ${ MgCO_3 <=> MgO(S) + CO_2 (g)}$

• A. ${ Kp = P_{CO_2}}$
• B. ${ Kp = P_{CO_2} \times \frac{P_{CO_2} \times P_{MgO}}{P_{MgCO_3}}}$
• C. ${ Kp = \frac{P_{CO_2} + P_{MgO}}{P_{MgCO_3}}}$
• D. ${ Kp = \frac{P_{MgCO_3}}{P_{CO_2} \times P_{MgO}}}$

Answer 1

Answer: (A)

${ Kp = P_{CO_2}}$

Answer 2

In heterogeneous system $K_c,K_p$ is not based upon concentratrion or pressure of solid substance. Hence, at equilibrium their concentration or pressure are assumed as one .
$\therefore \; {MgCO_3(g) <=> MgO(s) + CO_2 (g) }$
${K_p = P_{CO_2 }}$