In this example, it says to indicate whether each polymer rotates plane polarized light with 'y' for yes or 'n' for no. Remember, if you're going to rotate plane polarized light, that means you are chiral in nature. So if we take a look at the first one, this will be a 'no' because all these carbons, yes, they have chlorines with stereochemistry, but they're not chiral because they're not connected to 4 different groups. Each of them are connected to 2 chlorines. And the same thing with these methylene carbons, these CH₂ carbons, they're also connected to 2 hydrogens.

Now let's go to b. If we imagine that we can cut this in half, you would see that this side here looks like this side as though they're looking at each other in a mirror. There's an internal plane of symmetry, similar to what we learned about meso compounds. So here we'd say 'no'. Over here, again, if we just imagine there's a mirror right there.

Right? And we're looking on both sides here, we would say 'no'. And then this one here, this is random. Both sides don't look the same. So this would be chiral still.

So this would be a 'yes'. Alright. So that's how we'd approach each one of these polymers to determine if they're rotating plane polarized light, meaning they are chiral.