Answer:The expected product formed is 2-benzyl-5-phenylpent-2-enal .
Kindly refer the attachment for structure.
Step-by-step explanation:
3-phenylpropanal on reaction with sodium hydroxide undergoes an self- aldol condensation reaction and leads to formation of 2-benzyl-5-phenylpent-2-enal as final product.
In the first step of the reaction the highly basic hydroxide anions abstract a acidic hydrogen available at the carbon next to carbonyl carbon.These hydrogens are acidic because of the electron withdrawing effect of carbonyl group.
The proton abstraction leads to the generation of a carbanion and it further delocalizes forming an enolate anion.
The carbanion can behave as a nucleophile and can attack at the electrophilic carbon centers.
The carbonyl carbon is electrophilic in nature due to the electron withdrawl from oxygen which generates a partial positive charge on the carbonyl carbon.
The carbanion further reacts with another molecule of 3-phenylpropanal at its electrophilic carbonyl center and forms 2-benzyl-3-hydroxy-5-phenylpentanal. This reaction is known as self- aldol condensation reaction
2-benzyl-3-hydroxy-5-phenylpentanal has a OH group and this OH group is protonated through the available acidic protons from the solvent .
As OH is protonated it easily leaves leading to the formation of C=C double bond.
This reaction is one of the examples of Carbon-Carbon bond forming reaction.
Kindly refer attachments for reaction, structure and mechanism.