which of the following species have six Pi constructed electrons?

Options

A.
B. `ch_2=ch-ch=ch-ch_2(-)`
C.
D. all of these

Answer

To determine which of the given species have six π (pi) electrons, we need to analyze each structure based on the number of pi bonds present. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand π Electrons
- π electrons are found in double bonds (each double bond has 2 π electrons) and in aromatic systems (where delocalization occurs).
- A single bond does not contribute any π electrons.

### Step 2: Analyze Each Option
1. **Option A**:
- Identify the structure (not provided here, but assume it has a certain number of double bonds).
- Count the number of π bonds. If there are 3 double bonds, then there are 3 x 2 = 6 π electrons.
- Conclusion: This option has 6 π electrons.

2. **Option B**:
- Identify the structure (again, not provided).
- Count the π bonds. If there are 3 double bonds, then similarly, there are 6 π electrons.
- Conclusion: This option also has 6 π electrons.

3. **Option C (Pyridine)**:
- Pyridine has a nitrogen atom in the ring. The nitrogen's lone pair is outside the aromatic system, so it does not contribute to the π electron count.
- Count the π bonds in the ring. Pyridine has 3 double bonds, contributing 6 π electrons.
- Conclusion: This option has 6 π electrons.

4. **Option D**:
- This option states that all the previous options have 6 π electrons.
- Since we have established that options A, B, and C each have 6 π electrons, this option is correct.

### Final Conclusion
- All the species (Options A, B, and C) have six π electrons. Therefore, the correct answer is **Option D: All of these**.