Compounds which have CH3CO- group or compounds that can be converted to CH3CO- group undergo aldol condensation.

1-propanol doesn't undergo aldol condensation. However 2-propanol undergoes aldol condensation.

Aldol condensation is the reaction of two aldehydes in the presence of a basic catalyst. The aldol condensation leads to an aldol product, in which an hydroxyl group is attached to the beta carbon of an aldehyde.

Claisen condensation is similar to aldol condensation, but is involves two esters instead of two aldehydes. The product of a Claisen condensation is a beta-keto-ester, a compound characterized by an ester with its alpha carbon being a ketone.

Only those aldehydes may undergo the aldol condensation which have the alpha hydrogen (hydrogen at carbon adjacent to carbonyl carbon) in benzaldehyde alpha carbon is not present so it can not undergoes the aldol condensation.

All condensation reactions proceed with formation of water (H2O). If you look at the reaction mechanism for Aldol condensation, you will observe that water is formed as an end-product of the reaction.

The Claisen-Schmidt reaction involves the condensation of two carbonyl compounds, typically an aldehyde and a ketone, to form an α,β-unsaturated carbonyl compound. In contrast, aldol condensation involves the condensation of an aldehyde or ketone with itself to form a β-hydroxy carbonyl compound. The key difference is the presence of two different carbonyl compounds in the Claisen-Schmidt reaction, while aldol condensation involves one carbonyl compound reacting with itself.