Question

The following equation represents a reversible decomposition:

CaCO₃(s)⇌CaO(s)+CO₂(g)

Under what conditions will decomposition in a closed container proceed to completion so that no CaCO₃ remains?

Select one:

a. The amount of CaCO₃ must be equal to the amount of CO₂ and CaO

b. The amount of CaCO₃ must be very large.

c. The amount of CaCO_3 must be very small.

d. None of the above.

Answer 1

The decomposition of CaCO3 in a closed container will proceed to completion when the partial pressure of CO2 is kept low, usually by allowing the CO2 to escape the system, driving the reaction to completion. The correct option is c.

Step-by-step explanation:

The question is regarding the conditions under which the reversible decomposition of CaCO3 to CaO and CO2 will proceed to completion in a closed container. To achieve this, one has to manipulate the reaction conditions as per Le Châtelier's Principle.

The correct condition that will allow the decomposition of CaCO3 to go to completion, so that no CaCO3 remains, is an option not explicitly provided in the question. The essential factor is to maintain a low partial pressure of CO2. This can be accomplished by allowing the CO2 to escape the system, thus driving the reaction to the right.

It is not about the amounts of CaCO3, CaO, or CO2 initially present, but rather about maintaining conditions that continuously remove CO2 from the system. The correct option is c.