Question

Which of the following substances on heating does not liberate carbon dioxide ?

• A. Calcium carbonate
• B. Copper(II) carbonate
• C. Sodium hydrogen carbonate
• D. Sodium carbonate

Answer 1

The correct option is D

Sodium carbonate

Solution:

Calcium carbonate$\left({\mathrm{CaCO}}_3\right)$, copper(II) carbonate$\left({\mathrm{CuCO}}_3\right)$, and sodium hydrogen carbonate $\left({\mathrm{NaHCO}}_3\right)$ liberate carbon dioxide$\left({\mathrm{CO}}_2\right)$ on heating.

The explanation for the correct option:

Sodium carbonate ${\mathrm{Na}}_2{\mathrm{CO}}_3$ does not decompose easily as it is a highly stable carbonate and it has a very high melting point.

The Explanation for incorrect options:

A)Calcium carbonate $\left({\mathrm{CaCO}}_3\right)$ on heating decomposes into calcium oxide $\left(\mathrm{CaO}\right)$ and carbon dioxide$\left({\mathrm{CO}}_2\right)$.

Chemical equation: ${\mathrm{CaCO}}_3\stackrel{∆}{\to }\mathrm{CaO}+{\mathrm{CO}}_2$

B)Copper carbonate $\left({\mathrm{CuCO}}_3\right)$ on heating decomposes into copper oxide $\left(\mathrm{CuO}\right)$and carbon dioxide $\left({\mathrm{CO}}_2\right)$ .

Chemical equation: ${\mathrm{CuCO}}_3\stackrel{∆}{\to }\mathrm{CuO}+{\mathrm{CO}}_2$

C)Sodium hydrogen carbonate $\left({\mathrm{NaHCO}}_3\right)$ on heating decomposes to sodium carbonate$\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$,water, and carbon dioxide.

Chemical equation: $2\mathrm{Na}{\mathrm{HCO}}_3\stackrel{∆}{\to }{\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

Final answer: Therefore, the correct option is D.