Assertion (A) : Baking soda `(NaHCO_(3))` is a compound.
Reason (R ) : Properties `NaHCO_(3)` are absolutely different from sodium, carbon, hydrogen and oxygen.

Options

A. Both A and R are true and R is the correct explanation for A.
B. Both A and R are true but R is not the correct explanation for A.
C. A is true and R false.
D. A is false and R is true.

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that baking soda, chemically represented as NaHCO₃, is a compound.
- A compound is defined as a substance formed when two or more elements chemically combine in a fixed ratio.

2. **Identifying the Components of Baking Soda**:
- Baking soda consists of four elements: sodium (Na), hydrogen (H), carbon (C), and oxygen (O).
- These elements combine in a specific ratio: one sodium atom, one hydrogen atom, one carbon atom, and three oxygen atoms.

3. **Understanding the Reason (R)**:
- The reason states that the properties of NaHCO₃ are absolutely different from those of its constituent elements (sodium, carbon, hydrogen, and oxygen).
- This is true because the properties of compounds are often very different from the properties of the individual elements that make them up.

4. **Analyzing the Truth of Assertion and Reason**:
- Both the assertion and the reason are true statements.
- The reason provides a correct explanation for the assertion, as it highlights the difference in properties between the compound (baking soda) and its constituent elements.

5. **Conclusion**:
- Therefore, both the assertion (A) and the reason (R) are true, and the reason is the correct explanation of the assertion.

### Final Answer:
- **Assertion (A)** is true: Baking soda (NaHCO₃) is indeed a compound.
- **Reason (R)** is true: The properties of NaHCO₃ are absolutely different from those of sodium, carbon, hydrogen, and oxygen, and this explains why NaHCO₃ is classified as a compound.

---