Which does not show resonance ?

Options

A. Benzene
B. Aniline
C. Ethyl amine
D. Toluene

Answer

To determine which compound does not show resonance among the given options (benzene, aniline, ethylamine, and toluene), we will analyze each compound step by step.

### Step 1: Understand Resonance
Resonance is a concept in chemistry where a molecule can be represented by two or more valid Lewis structures. These structures differ only in the arrangement of electrons, not in the arrangement of atoms. Resonance structures help to describe the delocalization of electrons within a molecule.

**Hint:** Remember that resonance involves multiple valid Lewis structures that contribute to the overall structure of the molecule.

### Step 2: Analyze Benzene
Benzene (C6H6) has a cyclic structure with alternating double bonds. It can be represented by two resonance structures, which show the delocalization of π electrons across the carbon atoms.

**Hint:** Look for cyclic compounds with alternating double bonds for resonance.

### Step 3: Analyze Aniline
Aniline (C6H5NH2) has a benzene ring attached to an amino group (-NH2). The lone pair of electrons on the nitrogen can participate in resonance with the benzene ring, allowing for the delocalization of electrons.

**Hint:** Check if the molecule has a lone pair that can interact with a π system for resonance.

### Step 4: Analyze Toluene
Toluene (C6H5CH3) is similar to benzene but has a methyl group (-CH3) attached. The resonance structures of toluene are similar to those of benzene, with the delocalization of electrons occurring in the benzene ring.

**Hint:** Methyl groups do not affect resonance; they can still allow for resonance in the benzene part of the molecule.

### Step 5: Analyze Ethylamine
Ethylamine (C2H5NH2) has an ethyl group attached to an amino group. In this case, the lone pair of electrons on the nitrogen atom is localized and does not participate in resonance with any π system. Therefore, ethylamine does not exhibit resonance.

**Hint:** Look for compounds where lone pairs are localized and do not interact with double bonds or π systems.

### Conclusion
Based on the analysis, the compound that does not show resonance is **ethylamine (option C)**.

### Final Answer
C. Ethylamine does not show resonance.