 Okay, so today we're going to be talking about alkyne, so there's a couple of different kinds of alkynes. So we recall alkynes are molecules that have a triple bond as a functional group in their structure somewhere. So if we look at these two alkynes, hopefully you can tell that they're alkynes with the triple bond there. Hopefully you can see this one here has one R group off of the alkyne function, right? Here we have two of our groups off of the alkyne function. Does everybody see that? So these are effectively different types of alkynes, okay? So this one here of course has a hydrogen there. These kinds of alkynes are called terminal alkynes. Why? Because the alkyne substituent is at the terminus of the structure. These kinds of alkynes here are called internal alkynes, okay? Why is that? Because the alkyne function is internal of that carbon chain, okay? So the thing about terminal alkynes is these have, and you well know this from chapter I think one or two, they have an acidic proton. So this hydrogen right here is acidic. So it's got a pKa of, let's see what they're saying in your book. So about 25, so if we look at our pKa table, the pKa of that hydrogen, we'll say it's 25, okay? So if you have a strong base, it's going to deprotonate that hydrogen. Does that make sense? Okay, so are there any questions about this nomenclature?