The total number of Aldols `(beta-` Hydroxy carbonyl compounds) are formed in the following reaction. (Ignore stereoisomers)
`PhCHO+CH_(3)CH=O+Ph-underset(O)underset(||)(C)-CH_(3) overset(Dil.NaOH.Delta) (rarr)`

Explanation

To determine the total number of aldols (β-hydroxy carbonyl compounds) formed in the reaction of the compounds given, we will analyze each compound for the presence of alpha hydrogens and the potential aldol condensation reactions that can occur.

### Step-by-Step Solution:

1. **Identify the Compounds:**
The compounds involved in the reaction are:
- Benzaldehyde (PhCHO)
- Acetaldehyde (CH3CHO)
- Acetophenone (PhC(O)CH3)

2. **Check for Alpha Hydrogens:**
- **Benzaldehyde (PhCHO):**
- There are no alpha hydrogens because there is no sp3 hybridized carbon adjacent to the carbonyl carbon.
- **Acetaldehyde (CH3CHO):**
- There are 3 alpha hydrogens (from the CH3 group).
- **Acetophenone (PhC(O)CH3):**
- There are also 3 alpha hydrogens (from the CH3 group).

3. **Aldol Condensation Reactions:**
- Since PhCHO has no alpha hydrogens, it cannot undergo aldol condensation.
- Acetaldehyde (CH3CHO) can undergo aldol condensation with itself:
- **Reaction 1:** CH3CHO + CH3CHO → β-hydroxybutyraldehyde (one product).
- Acetophenone (PhC(O)CH3) can also undergo aldol condensation with itself:
- **Reaction 2:** PhC(O)CH3 + PhC(O)CH3 → β-hydroxyacetophenone (one product).

4. **Mixed Aldol Reactions:**
- **Acetaldehyde with Acetophenone:**
- **Reaction 3:** CH3CHO + PhC(O)CH3 can yield a product.
- The negative charge from the alpha hydrogen of acetaldehyde can attack the carbonyl carbon of acetophenone.
- **Acetophenone with Acetaldehyde:**
- **Reaction 4:** PhC(O)CH3 + CH3CHO can yield another product.
- The negative charge from the alpha hydrogen of acetophenone can attack the carbonyl carbon of acetaldehyde.

5. **Count the Total Products:**
- From **Reaction 1:** 1 product from CH3CHO + CH3CHO.
- From **Reaction 2:** 1 product from PhC(O)CH3 + PhC(O)CH3.
- From **Reaction 3:** 1 product from CH3CHO + PhC(O)CH3.
- From **Reaction 4:** 1 product from PhC(O)CH3 + CH3CHO.

6. **Final Count of Aldols:**
- Total aldol products formed = 1 (from CH3CHO) + 1 (from PhC(O)CH3) + 1 (from mixed reaction 1) + 1 (from mixed reaction 2) = **4 aldol products.**

### Conclusion:
The total number of aldols formed in the reaction is **4**.