MCQ
Which of the carbonates given below is unstable in air and is kept in $\ce{CO_2}$ atmosphere to avoid decomposition.
- A$\ce{BeCO_3}$
- B$\ce{MgCO_3}$
- C$\ce{CaCO_3}$
- ✓$\ce{BaCO_3}$
✓
Answer
Correct option: D.
$\ce{BaCO_3}$
Due to least electropositive character or least basicity of $\ce{Be,BeCO_3}$ is less stable and hence decomposes to give $\ce{BeO}$ and $\ce{CO_2}$.
$\text{BeCO}_3\xrightarrow{}\text{BeO}+\text{CO}_2$
Since the decomposition reaction is reversible, therefore, to increase the stability of $\ce{BeCO_3}$ or to reverse the above equilibrium, $\ce{BeCO_3}$ is kept in an atmosphere of $\ce{CO_2}$.
$\text{BeCO}_3\xrightarrow{}\text{BeO}+\text{CO}_2$
Since the decomposition reaction is reversible, therefore, to increase the stability of $\ce{BeCO_3}$ or to reverse the above equilibrium, $\ce{BeCO_3}$ is kept in an atmosphere of $\ce{CO_2}$.
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