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Reason for more stable eclipsed conformer of propene, propanal, ethanal

My textbook states that

Eclipsed confirmation of propene, ethanal, propanal is the most stable.

My friend said that it could be due to dipole-dipole interaction, $\ce{C1}$ of propene is $\delta^+$ and it could interact with H of $\ce{C3}$ to stabilise it, similarly others could be explained.

But if we apply similar reasoning to ethylene glycol or ethylene cyanohydrin, eclipsed conformer should be more stable, contrary to gauche conformer, as known. Also, how strong are these interactions that they outrace van der Wall strain and torsional strain. Also are there more such examples where eclipsed conformation is the most stable?

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