This section contains Assertion and Reason type questions .Each question has 4 choices (1)(2)(3) and (4) out of which only one is correct
Assertion(A):on heating calcium carbonate decomposes to give calcium oxide and carbon dioxide
Reason:Thermal decomposition reactions use the energy in the from of heat

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that upon heating, calcium carbonate (CaCO₃) decomposes into calcium oxide (CaO) and carbon dioxide (CO₂).
- This is a well-known reaction in chemistry, specifically a thermal decomposition reaction.

2. **Chemical Equation:**
- The thermal decomposition of calcium carbonate can be represented by the following chemical equation:
\[ \text{CaCO}_3 (s) \xrightarrow{\text{heat}} \text{CaO} (s) + \text{CO}_2 (g) \]

3. **Understanding the Reason:**
- The reason provided states that thermal decomposition reactions utilize energy in the form of heat.
- This is accurate as thermal decomposition requires heat to break down the compound into its constituent parts.

4. **Analyzing the Relationship:**
- Both the assertion and the reason are true statements.
- The assertion correctly describes the decomposition of calcium carbonate, and the reason correctly explains the nature of thermal decomposition reactions.

5. **Conclusion:**
- Since both the assertion and the reason are true and the reason supports the assertion, the correct choice is:
- (1) Both A and R are true, and R is the correct explanation of A.

**Final Answer: (1)**

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