Non-rotating pi bonds

[Sean Wang 1F]

Why is it important that pi bonds cannot rotate, while sigma bonds can? What types of problems do we apply this to and how?

[Jeffrey Hablewitz 2I]

The fact that pi bonds cant rotate affects the shape, and therefore reactivity, of some molecules. It is particularly important in the shape of organic molecules. This website has a pretty good description : https://chem.libretexts.org/Courses/Sac ... c%20nature.
In terms of problems regarding pi bonds, I believe we the importance of pi bonds in the formation of the cis and trans isomers of 1,2 dichloromethane in lecture.

[America Ramirez 3H]

the shape of the pi bond is basically like a ladder where you have two regions in the p-orbital that overlap and you cannot rotate one of the overlapping parts or a step in a ladder without breaking the whole thing. But with sigma bonds, since there is only one point of overlap it can rotate freely without breaking the actual bond.