Assertion Both `NO_(3)^(Theta)` and `CO_(3)^(2-)` ions are triangular planar
Reasoning Hybridisation of central atom in both `NO_(3)^(Theta)` and `CO_(3)^(2-)` is sp^(2)` .

Options

A. If both `(A)` and `(R )` are correct and `(R )` is the correct explanation of `(A)`
B. If both `(A)` and `(R )` are correct and `(R )` is the correct explanation of `(A)`
C. If `(A)` is correct but `(R )` is incorrect
D. If `(A)` is incorrect but `(R )` is correct

Explanation

To solve the question, we need to analyze both the assertion and the reasoning statements provided.

### Step 1: Analyze the Assertion
The assertion states that both \( \text{NO}_3^- \) (nitrate ion) and \( \text{CO}_3^{2-} \) (carbonate ion) are trigonal planar.

- **Nitrate Ion \( \text{NO}_3^- \)**:
- Nitrogen (N) is the central atom, and it is bonded to three oxygen (O) atoms.
- The Lewis structure shows that nitrogen forms three bonds with oxygen, and there is one lone pair on nitrogen.
- The arrangement of the three oxygen atoms around nitrogen leads to a trigonal planar geometry.

- **Carbonate Ion \( \text{CO}_3^{2-} \)**:
- Carbon (C) is the central atom, and it is bonded to three oxygen (O) atoms.
- The Lewis structure shows that carbon forms one double bond with one oxygen and single bonds with the other two oxygens, with a formal charge distribution that results in a trigonal planar shape.
- The arrangement of the three oxygen atoms around carbon also leads to a trigonal planar geometry.

Thus, the assertion is **correct**.

### Step 2: Analyze the Reasoning
The reasoning states that the hybridization of the central atom in both \( \text{NO}_3^- \) and \( \text{CO}_3^{2-} \) is \( \text{sp}^2 \).

- **Hybridization of Nitrogen in \( \text{NO}_3^- \)**:
- Nitrogen forms three sigma bonds (one with each oxygen) and has no lone pairs (considering resonance structures).
- The hybridization of nitrogen in this case is indeed \( \text{sp}^2 \).

- **Hybridization of Carbon in \( \text{CO}_3^{2-} \)**:
- Carbon also forms three sigma bonds (one with each oxygen).
- The hybridization of carbon in this case is also \( \text{sp}^2 \).

Thus, the reasoning is also **correct**.

### Conclusion
Both the assertion and reasoning are correct, and the reasoning correctly explains the assertion.

### Final Answer
Both statements are correct, and the second statement is the correct explanation for the first.