Consider the following carbocations
1 . `C_6H_5overset(+)CH_2`
2. `C_6H_5overset(+) CHCH_3`
3 `(C_6H_5)_2overset(+)CH`
4. `(C_6H_5)_3 overset(+)(C)`
The correct sequence of increasing order of thir stabilities is

Options

A. `1 lt 2 lt 4 lt 3`
B. `4 lt 2 lt 3 lt 1`
C. `1 lt 2 lt 3 lt 4`
D. `1 gt 2 gt 4 gt 3`

Answer

To determine the stability of the given carbocations, we need to analyze each structure and classify them based on their type (primary, secondary, or tertiary) and the resonance effects provided by the attached benzene rings.

### Step-by-Step Solution:

1. **Identify the Structure of Each Carbocation:**
- **Carbocation 1:** `C6H5-CH2+` (Benzyl cation) - This is a primary carbocation since the positively charged carbon is attached to only one carbon atom.
- **Carbocation 2:** `C6H5-CH+-CH3` (Benzyl cation with a methyl group) - This is a secondary carbocation because the positively charged carbon is attached to two other carbon atoms (one from the benzene and one from the methyl group).
- **Carbocation 3:** `(C6H5)2-CH+` (Diphenylmethyl cation) - This is also a secondary carbocation, as the positively charged carbon is attached to two benzene rings and one carbon.
- **Carbocation 4:** `(C6H5)3-C+` (Triphenylmethyl cation) - This is a tertiary carbocation because the positively charged carbon is attached to three benzene rings.

2. **Determine the Stability Order:**
- **Tertiary Carbocation (Carbocation 4)** is the most stable due to hyperconjugation and resonance from three benzene rings.
- **Secondary Carbocations (Carbocations 2 and 3)** are less stable than tertiary but more stable than primary. Between them, Carbocation 3 is more stable than Carbocation 2 due to the resonance stabilization from two benzene rings.
- **Primary Carbocation (Carbocation 1)** is the least stable as it has no additional stabilization from resonance.

3. **Final Stability Order:**
- The correct sequence of increasing order of stability is:
- Carbocation 1 (least stable)
- Carbocation 2
- Carbocation 3
- Carbocation 4 (most stable)

Thus, the increasing order of stability is:
**1 < 2 < 3 < 4**