In a lime kiln, to get higher yield of `CO_(2)`, the measure that can be taken is :
`[CaCO_(3)(s) rarr CO_(2)(g) + CaO(s)]`

Options

A. To remove `CaCO_(3)`
B. To add more CaO
C. To add `CO_(2)`
D. To pump out `CO_(2)`

Explanation

To solve the problem of increasing the yield of carbon dioxide (CO₂) in a lime kiln, we can analyze the chemical equilibrium involved in the reaction of calcium carbonate (CaCO₃) decomposing into calcium oxide (CaO) and carbon dioxide (CO₂). The balanced chemical equation for this reaction is:

\[ \text{CaCO}_3(s) \rightleftharpoons \text{CaO}(s) + \text{CO}_2(g) \]

### Step-by-Step Solution:

1. **Identify the Reaction**: The decomposition of calcium carbonate (CaCO₃) into calcium oxide (CaO) and carbon dioxide (CO₂) is an equilibrium reaction.

2. **Understand the Conditions**: The reaction occurs upon heating, typically at around 900°C. At this temperature, the equilibrium is established between the solid calcium carbonate, the solid calcium oxide, and the gaseous carbon dioxide.

3. **Apply Le Chatelier's Principle**: According to Le Chatelier's Principle, if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change and restore a new equilibrium.

4. **Decrease the Concentration of CO₂**: To increase the yield of CO₂, we can manipulate the conditions of the equilibrium. One effective method is to decrease the concentration of CO₂ in the system. This can be done by removing CO₂ gas from the kiln as it is produced.

5. **Conclusion**: By continuously pumping out or removing CO₂ gas from the kiln, we effectively lower its concentration in the reaction mixture. This shift in concentration will drive the equilibrium to the right, favoring the production of more CO₂ from the remaining CaCO₃, thus increasing the overall yield of CO₂.

### Final Answer:
To get a higher yield of carbon dioxide in a lime kiln, the measure that can be taken is to **pump out carbon dioxide**.

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