The incorrect statement about carbene `(CH_(2))` is :

Options

A. In singler carbene, carbon is `sp^(2)`-hybridized whereas in triplet carbene, carbon is sp-hybridized
B. Triplet carbene is less stable than singlet carbene
C. Stability order of singlet halocarbenes is :`CHFgtCHClgtCHBr`
D. None of the above

Explanation

To determine the incorrect statement about carbene (CH₂), we need to analyze the properties of both singlet and triplet carbene forms. Let's break down the information step by step.

### Step 1: Understanding Singlet and Triplet Carbene
- **Singlet Carbene (CH₂)**: In this state, the carbon atom is sp² hybridized. It has a lone pair of electrons and two hydrogen atoms bonded to it. The spin multiplicity is calculated as \(2s + 1\), where \(s\) is the total spin. For singlet carbene, the two electrons in the lone pair are paired, resulting in a spin multiplicity of 1.

- **Triplet Carbene (CH₂)**: In this state, the carbon atom is sp hybridized. It has two unpaired electrons and two hydrogen atoms bonded to it. The spin multiplicity is calculated similarly, and for triplet carbene, the two unpaired electrons each have a spin of +1/2, resulting in a total spin of 1 and a multiplicity of 3.

### Step 2: Analyzing Stability
- **Stability Comparison**: According to Hund's rule, the triplet state (with maximum multiplicity) is generally more stable than the singlet state. Therefore, the statement "triplet carbene is less stable than singlet carbene" is incorrect.

### Step 3: Hybridization and Steric Number
- For **singlet carbene**, the steric number is 3 (2 sigma bonds + 1 lone pair), confirming sp² hybridization.
- For **triplet carbene**, the steric number is 2 (2 sigma bonds), confirming sp hybridization.

### Step 4: Stability Order of Singlet Halocarbons
- The stability order of singlet halocarbons (CHF > CHCl > CHBr) is based on the effectiveness of back bonding. Fluorine has the best overlap with carbon due to its small size and high electronegativity, making CHF the most stable.

### Conclusion
Based on the analysis:
- The incorrect statement about carbene (CH₂) is: **"Triplet carbene is less stable than singlet carbene."**