The number of possible alkynes (strucutral only) for the compound having molecular formula `C_(3)FCIBrI` is:

Explanation

To determine the number of possible structural isomers of alkynes for the compound with the molecular formula \( C_3FClBrI \), we can follow these steps:

### Step 1: Identify the Carbon Backbone
The molecular formula indicates that there are 3 carbon atoms. For alkynes, we need at least 2 carbon atoms to form a triple bond. Therefore, the basic structure will be:

\[ C \equiv C - C \]

### Step 2: Determine the Number of Hydrogen Atoms
In a typical alkyne, the general formula is \( C_nH_{2n-2} \). For \( n = 3 \):

\[ H = 2(3) - 2 = 4 \]

However, in this case, the hydrogen atoms will be replaced by halogens (F, Cl, Br, I).

### Step 3: Identify Halogen Substitutions
We have four halogens (F, Cl, Br, I) that can replace the hydrogen atoms. We need to consider how these halogens can be arranged on the carbon skeleton.

### Step 4: Draw Possible Structural Isomers
1. **First Structure**: Place F on the first carbon, and Cl, Br, and I on the second and third carbons.
- Structure: \( F - C \equiv C - C(Br)(I) \)

2. **Second Structure**: Place Cl on the first carbon, and F, Br, and I on the second and third carbons.
- Structure: \( Cl - C \equiv C - C(F)(Br)(I) \)

3. **Third Structure**: Place Br on the first carbon, and F, Cl, and I on the second and third carbons.
- Structure: \( Br - C \equiv C - C(F)(Cl)(I) \)

4. **Fourth Structure**: Place I on the first carbon, and F, Cl, and Br on the second and third carbons.
- Structure: \( I - C \equiv C - C(F)(Cl)(Br) \)

### Step 5: Count the Unique Structures
From the arrangements above, we can see that there are 4 unique structural isomers for the alkynes with the given molecular formula.

### Final Answer
The number of possible structural isomers of alkynes for the compound \( C_3FClBrI \) is **4**.

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