Which of these molecules would you predict to have the largest number of polar covalent bonds based on their molecular formulas? a. C2H6O (ethanol) b. C2H6 (ethane) c. C2H4O2 (acetic acid) d. C3H8O (propanol)

Video transcript

Welcome back. Let's look at our next quest. Next question. Which of the following molecules has the highest number of electron pairs shared. Well let's recall that electron pairs are shared when they're in covalin bonds. Remembering that we can have more than one pair of electrons shared a single bond shares a single pair. But you can also have double and triple bonds sharing more electrons. So with that in mind let's look at our answer choices. Choice A is hcl hydrochloric acid and I'm gonna do that down here in blue. We've got hydrogen and chlorine, hydrogen can share one electron chlorine has seven and will happily share one in a bond. So we've got one bond here and here's the other six chlorine electrons there. So hcl we've got this one bond right here. So we're sharing too electrons electron pairs. So we're going to say one, we share one electron pair. Now this will switch to read for choice B, which is H 20. Water. We've got two hydrogen and oxygen. The hydrogen share one electron in a bond with oxygen, oxygen has six valence electrons. So it'll share one each with the hydrogen and then have four left as lone pairs. So we show here we've got two bonds And therefore two electron pairs shared in a molecule of water. Now let's go to the next one here which I will do in black ch 30. H. Which is methanol. We've got a carbon carbon likes to form four bonds as it has four valence electrons. So we'll put oxygen here as one of them and then three hydrogen around it. Each of those like to share one and then the oxygen has a hydrogen on the other side. So hydrogen is each sharing one carbon sharing one each year, sharing one with oxygen. Oxygen as we recall, has six valence electrons. It's sharing too. So then it's got two lone pairs for the other four. So we count up our bonds here, we have five pairs of electrons being shared. So methanol has five shared pairs. And finally we've got NH three ammonia. We'll do that in a purple color down here. Choice. DNH three. We've got our nitrogen with three hydrogen around it. Each of those hydrants, hydrogen is forming one bond, nitrogen having five valence electrons. It's sharing three in bonds and has a lone pair left. So that gives us three shared pairs of electrons. So that there, So when we look at our answer choices, it's pretty straightforward to see that choice. C methanol with its five shared pairs of electrons, has the highest number of electron pairs shared. See you in the next video