Here in this example question, it says identify the following molecule as chiral or achiral. Now here's a huge hint when it comes to chiral centers, remember the carbon must be connected to four unique groups. But if you're a double bonded or triple bonded carbon, it's not possible. If we take a look at this double bonded carbon for instance, carbon must make four bonds. It's making 1, 2, 3 bonds that we see. That fourth bond is that invisible hydrogen.

Now how many groups would that carbon be connected to? 1, 2, 3 can't get to 4. So if you have a double bond or triple bond for carbon, it can't be chiral. So that means we're ignoring all these carbons within this benzene ring, and we're focusing on this carbon here and this carbon here. The carbon on the far right, it's making one bond, so it has three hydrogens we don't see, definitely not chiral.

But this carbon here, it's making 1, 2, 3 bonds that we see. So it has one hydrogen that's invisible. So what groups is it connected to? Well, it's connected to this hydrogen, this OH group, this entire benzene, and then this CH₃ group. How many unique groups is that? That's four unique groups, which means that this carbon here is a chiral carbon, which means a molecule overall would be chiral. So here we're going to say the following molecule is a chiral molecule.