Question

O_2(g) is obtained on heating

• A. CaCO_3(s)
• B. C_6H_{12}O_6(s)
• C. Pb(NO_3)_2(s)
• D. Na_2CO_3(s)

Hint:

Remember: Calcium carbonate decomposes upon heating to release carbon dioxide and calcium oxide. This reaction is important for the industrial production of lime.

Answer 1

The Correct Option is A

Step 1: Decomposition Reaction of Calcium Carbonate
When calcium carbonate (CaCO\(_3\)) is heated, it undergoes a thermal decomposition reaction, producing calcium oxide (CaO) and carbon dioxide (CO\(_2\)). The oxygen gas is produced when the carbon dioxide is removed from the calcium carbonate. The reaction is as follows:
\[ \text{CaCO}_3 (s) \xrightarrow{\text{heat}} \text{CaO} (s) + \text{CO}_2 (g) \]

Step 2: Analyzing Other Options
- C\(_6\)H\(_{12}\)O\(_6\) (glucose) does not release oxygen upon heating. It undergoes a process called fermentation or combustion but not oxygen release directly.
- Pb(NO\(_3\))\(_2\) decomposes on heating to give lead(II) oxide (PbO), nitrogen dioxide (NO\(_2\)), and oxygen, but it does not directly give oxygen gas under normal conditions.
- Na\(_2\)CO\(_3\) does not release oxygen upon heating; it is a stable compound that does not decompose to give oxygen.

Step 3: Conclusion
Thus, the correct answer is that oxygen gas is obtained by heating CaCO\(_3\) (calcium carbonate).
\[ \boxed{\text{CaCO}_3} \]