When an aldehyde is treated with an excess of monohydric alcohol,what is formed?

$3$-hydroxybutanal is formed when $(X)$ reacts with $(Y)$ in dilute $(Z)$ solution. What are $X, Y$ and $Z$?

Would you expect $benzaldehyde$ to be more reactive or less reactive in nucleophilic addition reactions than $propanal$? Explain your answer.

The reaction shown below is:

Consider the following reaction. The structure of the main product will be

Trichloroacetaldehyde was subjected to Cannizzaro's reaction by using $NaOH$. The mixture of the products contains sodium trichloroacetate and another compound. The other compound is: