A rigid vessel at fixed temperature contains excess CaCO3(s), CaO(s) and C(s) in equilibrium with CO2(g) and CO(g) through CaCO3(s) CaO(s) + CO2(g) and C(s) + CO2(g) 2CO(g). The volume of the vessel is doubled (all solids remain present) and equilibrium is re-established. Which statements are correct?

The total gas pressure is unchanged

The amount of CaCO3(s) decreases

The total gas pressure is unchanged

The amount of CaCO3(s) decreases

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ce108

A rigid vessel at fixed temperature contains excess $CaCO X_{3} (s)$ , $CaO (s)$ and $C (s)$ in equilibrium with $CO X_{2} (g)$ and $CO (g)$ through $CaCO X_{3} (s) CaO (s) + CO X_{2} (g)$ and $C (s) + CO X_{2} (g) 2 CO (g)$ . The volume of the vessel is doubled (all solids remain present) and equilibrium is re-established. Which statements are correct?

With both

CaCO X_{3}

and

CaO

present,

p_{CO X_{2}} = K_{p 1}

is fixed, and then

p_{CO} = K_{p 2} K_{p 1}

is also fixed, so the total pressure and the ratio

p_{CO} / p_{CO X_{2}}

do not change. Since

n = p V / RT

and

V

doubles at constant

p

, the moles of each gas double, which needs extra

CO X_{2}

from

CaCO X_{3}

(its amount decreases) and carbon is used up to make more

CO

. Statements 1, 2 and 3 are correct.