Assertion : Two nodal planes are present in `3d_(xy)`.
Reason : Number of nodal planes = 1

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.
C. If Assertion is true statement but Reason is false.
D. If both Assertion and Reason are false statements.

Answer

To solve the assertion-reason question regarding the nodal planes in the 3d_(xy) orbital, we can break down the solution into the following steps:

### Step 1: Understand the Assertion
The assertion states that "Two nodal planes are present in 3d_(xy)." We need to analyze the structure of the 3d_(xy) orbital to confirm this statement.

**Hint:** Recall that nodal planes are regions in an orbital where the probability of finding an electron is zero.

### Step 2: Analyze the 3d_(xy) Orbital
The 3d_(xy) orbital has a cloverleaf shape and is oriented in the xy-plane. It has regions of positive and negative amplitude, which indicates the presence of nodal planes.

**Hint:** Visualize the 3d_(xy) orbital in a three-dimensional coordinate system to identify the nodal planes.

### Step 3: Identify Nodal Planes
In the case of the 3d_(xy) orbital, there are indeed two nodal planes:
1. The xz-plane
2. The yz-plane

These planes divide the orbital into regions where the probability of finding an electron is zero.

**Hint:** Remember that the number of nodal planes in a d-orbital is generally given by the formula \( n - l - 1 \), where \( n \) is the principal quantum number and \( l \) is the azimuthal quantum number.

### Step 4: Understand the Reason
The reason states that "Number of nodal planes = 1." This is incorrect for the 3d_(xy) orbital, as we have established that there are two nodal planes.

**Hint:** Compare the assertion with the reason to see if they are consistent with each other.

### Step 5: Conclusion
Since the assertion is true (there are two nodal planes in the 3d_(xy) orbital) and the reason is false (the number of nodal planes is not one), we conclude that the correct answer is that the assertion is true, but the reason is false.

**Final Answer:** The assertion is true, and the reason is false.