The Newman projection formula of the most stable conformation of $3-\text{Hydroxypropanal}$ is stable due to the

In the given conformation ${\mathrm{C}}_2$ is rotated about ${\mathrm{C}}_2 - {\mathrm{C}}_3$ bond anticlockwise by an angle of $120°$, then the conformation obtained is

The identical compounds are

Which Newman projection shows the most stable conformation of the following compound?

Consider the following molecules:

Choose the correct comparison of stability:

Which of the following represent most stabilised conformer of

Group at $\mathrm{I} \text{and} \mathrm{IV}$ positions are trans to each other. 

In the given four conformational isomers which of the following has minimum torsional strain and minimum van der Waal's strain