Which of the following is an acceptable value of molecularity ?

Options

A. 5
B. 0
C. `3//2`
D. 2

Explanation

To determine which of the following is an acceptable value of molecularity, we need to understand the concept of molecularity in chemical kinetics. Here’s a step-by-step solution:

### Step 1: Define Molecularity
Molecularity is defined as the number of reactant molecules that collide simultaneously to bring about a chemical reaction.

### Step 2: Identify Acceptable Values
1. **Molecularity cannot be zero**: Since at least one molecule is required to initiate a reaction, molecularity cannot be zero.
2. **Molecularity cannot be fractional**: Molecularity must be a whole number. For example, a value of 1.5 is not acceptable because you cannot have a fraction of a molecule participating in a reaction.
3. **Molecularity cannot be greater than 3**: Reactions involving more than three molecules colliding simultaneously are extremely rare and generally ineffective due to the low probability of simultaneous collisions.

### Step 3: Evaluate Given Options
Now, let's evaluate the options provided in the question:
- **Option 0**: Not acceptable (molecularity cannot be zero)
- **Option 3/2 (1.5)**: Not acceptable (molecularity cannot be fractional)
- **Option 5**: Not acceptable (molecularity cannot be greater than 3)
- **Option 2**: Acceptable (molecularity can be 1, 2, or 3)

### Conclusion
The only acceptable value of molecularity from the given options is **2**.