Resonance is not possible in

Options

A.
B.
C.
D.

Answer

To determine which compound does not exhibit resonance, we can analyze the given options step by step.

### Step 1: Identify the Compounds
We need to analyze the compounds given in the options. Let's denote them as:
- Option 1: Compound with a positive charge and an oxygen with a lone pair.
- Option 2: NH3 with a positive charge on nitrogen.
- Option 3: NO2.
- Option 4: BH2 with a double bond.

### Step 2: Analyze Option 1
For the first compound, we have a positive charge and a lone pair on oxygen. The oxygen can donate its lone pair to form a double bond with the adjacent atom, leading to resonance structures. Therefore, resonance is possible in this compound.

**Hint:** Look for lone pairs and charges that can participate in resonance.

### Step 3: Analyze Option 2
In the second option, we have NH3 with a positive charge on nitrogen. Here, nitrogen has four bonds (three with hydrogen and one with a positive charge). Since nitrogen cannot exceed four bonds, there is no possibility of forming a resonance structure. Thus, resonance is not possible in this compound.

**Hint:** Remember that elements like nitrogen cannot exceed their maximum bonding capacity.

### Step 4: Analyze Option 3
In the third option, we have NO2. This compound can exhibit resonance because the double bond between nitrogen and one oxygen can shift, allowing for the formation of different resonance structures. Therefore, resonance is possible in this compound.

**Hint:** Check for the ability to shift double bonds and lone pairs to create alternative structures.

### Step 5: Analyze Option 4
For the fourth option, we have BH2 with a double bond. Boron can accept an electron pair and can form multiple bonds. Therefore, resonance structures can also be formed in this case.

**Hint:** Consider the ability of elements like boron to form additional bonds due to their electron deficiency.

### Conclusion
After analyzing all the options, we find that the compound in **Option 2 (NH3 with a positive charge on nitrogen)** does not exhibit resonance.

### Final Answer
The answer to the question "Resonance is not possible in" is **Option 2**.