1) Draw the structure of the hydroxyaldehyde product from the self-aldol reaction of each of the following aldehydes: (a) propanal; (b) phenylethanal; (c) 3-phenylpropanal; (d) benzaldehyde.

2) Draw the structure of the α,β-unsaturated aldehyde product from the self-aldol reaction of each of the aldehydes in question 1.