The product which is not formed in the following reactions :
`{:(" "CH_(3)" "CH_(3)),(" |"" |"),(" "Ph-C-CH-CH-CH-CH_(2)OH overset(HIO_(4)"(excess)")rarr),(" |"" |"" |"),(" "OH" "OH" "OH):}`

Options

A. `HCOOH`
B. `Ph-overset(O)overset(||)(C)-CH_(3)`
C. `OHC-overset(CH_(3))overset(|)(CH)-CH_(2)OH`
D. `OHC-overset(CH_(3))overset(|)(CH)-CHO`

Answer

To solve the question regarding the product that is not formed in the reaction of the given compound with excess HIO4, we will follow these steps:

### Step 1: Understand the Reactant Structure
The reactant is a compound with a phenyl group (Ph), hydroxyl groups (OH), and a chain of carbon atoms. The structure can be represented as:
```
Ph-C(OH)-C(OH)-C(OH)-C(CH3)-CH2OH
```
This compound has multiple hydroxyl groups that can react with HIO4.

**Hint:** Identify the functional groups in the reactant structure and their positions.

### Step 2: Reaction with HIO4
HIO4 (periodic acid) is known to cleave vicinal diols (two hydroxyl groups on adjacent carbons). In this case, the compound has several hydroxyl groups that can undergo oxidation and cleavage.

**Hint:** Recall that HIO4 cleaves diols to form carbonyl compounds.

### Step 3: Determine Possible Products
When the compound reacts with excess HIO4, the following transformations can occur:
1. Cleavage of the C-C bond between the hydroxyl groups leading to the formation of aldehydes or ketones.
2. The products can include:
- Formic acid (HCOOH)
- Aldehydes from the cleavage of the carbon chain
- Other carbonyl compounds depending on the structure.

**Hint:** Consider the types of products that can be formed from the cleavage of each hydroxyl group.

### Step 4: Identify the Products
From the reaction, the products that can be formed include:
- HCOOH (formic acid)
- CH3CHO (acetaldehyde)
- Other carbonyl compounds depending on the structure.

**Hint:** List the products formed and compare them with the options given in the question.

### Step 5: Compare with Given Options
Now, we need to compare the products formed with the options provided in the question. The question asks for the product that is NOT formed.

After analyzing the products:
- If the options include HCOOH, CH3CHO, and other carbonyl compounds, we need to identify which one does not appear in the reaction products.

**Hint:** Check each option against the products formed to find the one that is missing.

### Conclusion
After evaluating the products formed from the reaction of the given compound with excess HIO4, we find that one of the options does not correspond to any of the products formed in the reaction. Thus, that option is the correct answer to the question.

**Final Answer:** The product which is not formed in the reaction is **Option 4**.