0:00:00.000,0:00:00.610


0:00:00.610,0:00:02.120
Let's think a little bit[br]about some of the

0:00:02.120,0:00:03.820
properties of alcohol.

0:00:03.820,0:00:07.260
So the general formula for an[br]alcohol we saw is some type of

0:00:07.260,0:00:12.050
group or chain of carbons bonded[br]to an oxygen, bonded to

0:00:12.050,0:00:13.210
a hydrogen.

0:00:13.210,0:00:15.980
And of course, the oxygen[br]will have two lone

0:00:15.980,0:00:17.220
pairs just like that.

0:00:17.220,0:00:19.060
Let's compare this to water.

0:00:19.060,0:00:20.680
So water just looks like this.

0:00:20.680,0:00:24.260
You have a hydrogen bonded to[br]an oxygen, bonded to another

0:00:24.260,0:00:27.190
hydrogen with two lone pairs.

0:00:27.190,0:00:30.960
Now in the case of water,[br]the oxygen is much more

0:00:30.960,0:00:33.090
electronegative than the[br]hydrogen, so it hogs the

0:00:33.090,0:00:34.350
electrons towards it.

0:00:34.350,0:00:39.620
So you have a partial negative[br]charge at the oxygen end.

0:00:39.620,0:00:45.060
Then you have partial positive[br]charges at the hydrogen ends.

0:00:45.060,0:00:49.600
That's what allows oxygen to[br]kind of-- or sorry-- that's

0:00:49.600,0:00:54.680
what allows water to bond to[br]itself or to have not a

0:00:54.680,0:00:56.910
ridiculously low[br]boiling point.

0:00:56.910,0:00:58.580
So let me show this.

0:00:58.580,0:00:59.980
Let me copy and paste this.

0:00:59.980,0:01:02.680
We've seen all this before[br]in regular chemistry.

0:01:02.680,0:01:04.099
So copy and paste.

0:01:04.099,0:01:07.180
So let me draw some more[br]water molecules here.

0:01:07.180,0:01:09.740
Let me draw another water[br]molecule here.

0:01:09.740,0:01:13.320
So you see water because the[br]oxygen end has a partial

0:01:13.320,0:01:15.570
negative charge and the hydrogen[br]ends have partial

0:01:15.570,0:01:19.210
positive charges, the oxygen of[br]one water molecule will be

0:01:19.210,0:01:22.710
attracted to the hydrogen of[br]another water molecule.

0:01:22.710,0:01:24.390
And we've seen this before.

0:01:24.390,0:01:26.580
This we call hydrogen bonding.

0:01:26.580,0:01:28.905
So that right there is[br]hydrogen bonding.

0:01:28.905,0:01:32.530


0:01:32.530,0:01:35.940
The exact same thing can happen[br]with alcohols, although

0:01:35.940,0:01:38.290
alcohols really only have[br]the partial positive

0:01:38.290,0:01:39.120
charge on the hydrogen.

0:01:39.120,0:01:41.060
We don't know exactly what's[br]going on here.

0:01:41.060,0:01:44.500
We probably have carbons[br]bonded to the oxygen.

0:01:44.500,0:01:48.200
And with the carbons, they're[br]reasonably electronegative.

0:01:48.200,0:01:50.580
They're not going to have their[br]electrons hogged as much

0:01:50.580,0:01:52.130
as a hydrogen would.

0:01:52.130,0:01:56.620
So in the case of an alcohol--[br]let me draw.

0:01:56.620,0:01:59.250
Instead of having this R for[br]radical there, let me make it

0:01:59.250,0:02:00.290
a little bit more concrete.

0:02:00.290,0:02:03.140
Let me draw an actual alcohol.

0:02:03.140,0:02:04.580
So an actual alcohol.

0:02:04.580,0:02:06.400
Maybe we have methanol.

0:02:06.400,0:02:10.620
Maybe we have methanol that[br]would look like that.

0:02:10.620,0:02:13.060
It has a hydrogen[br]right over here.

0:02:13.060,0:02:16.630
Oxygen is much more[br]electronegative than the

0:02:16.630,0:02:19.490
hydrogen, so you have a partial[br]negative charge there.

0:02:19.490,0:02:22.680
And then you have a partial[br]positive charge there.

0:02:22.680,0:02:27.220
So it too, because of these[br]hydrogen bonds, it will have a

0:02:27.220,0:02:28.500
reasonable boiling point.

0:02:28.500,0:02:30.850
It won't just turn immediately[br]into the gaseous state.

0:02:30.850,0:02:33.576
It would actually try to[br]bond to each other.

0:02:33.576,0:02:36.750
Let me copy and paste that.

0:02:36.750,0:02:38.680
So it can also form the[br]hydrogen bonds.

0:02:38.680,0:02:42.030
Although they won't to be quite[br]as strong as what you

0:02:42.030,0:02:42.660
see in water.

0:02:42.660,0:02:46.770
And that's why something like[br]methanol actually has a lower

0:02:46.770,0:02:47.950
boiling point than water.

0:02:47.950,0:02:49.390
It's easy to make it boil.

0:02:49.390,0:02:52.470
It's easier to make these bonds[br]break apart because you

0:02:52.470,0:02:54.980
don't have as much of the[br]hydrogen bonding.

0:02:54.980,0:02:57.320
So this is an example[br]of hydrogen

0:02:57.320,0:02:59.360
bonding with methanol.

0:02:59.360,0:03:03.575
Now because methanol can have[br]hydrogen bonding and it has

0:03:03.575,0:03:06.920
this slight polarity to it and[br]water obviously has hydrogen

0:03:06.920,0:03:11.390
bonding, methanol is actually[br]miscible in water.

0:03:11.390,0:03:14.430
And all that means is that it's[br]soluble in water in any

0:03:14.430,0:03:15.020
proportion.

0:03:15.020,0:03:17.380
No matter how much methanol[br]or how much water

0:03:17.380,0:03:18.900
you have, it is soluble.

0:03:18.900,0:03:23.690
So if I were to draw some[br]methanol molecules-- actually,

0:03:23.690,0:03:25.110
maybe this is the water[br]right here.

0:03:25.110,0:03:29.380
So if you draw a methanol[br]molecule right there, that

0:03:29.380,0:03:31.580
would have a hydrogen bond[br]right over there.

0:03:31.580,0:03:34.690
If I were to draw another[br]methanol molecule maybe right

0:03:34.690,0:03:39.590
over here, you would have[br]another hydrogen bond right

0:03:39.590,0:03:40.250
over there.

0:03:40.250,0:03:42.470
And that's what allows[br]methanol to

0:03:42.470,0:03:44.730
be soluble in water.

0:03:44.730,0:03:48.930
Now, as this chain grows, or[br]if you have alcohols with

0:03:48.930,0:03:53.140
longer radical chains, then[br]they become less and less

0:03:53.140,0:03:54.060
soluble in water.

0:03:54.060,0:03:55.980
But their boiling points[br]actually do go up.

0:03:55.980,0:03:57.640
And let's think about[br]why that is.

0:03:57.640,0:04:01.760
So if I have something like--[br]let me do butanol.

0:04:01.760,0:04:03.430
So butanol's going to[br]have 4 carbons.

0:04:03.430,0:04:10.100
So it's going to be H3C, H3--[br]let me just draw it like H3C,

0:04:10.100,0:04:17.260
CH2, Ch2, CH-- let me[br]do it like this.

0:04:17.260,0:04:19.579
H2C.

0:04:19.579,0:04:22.440
Then that carbon, that last[br]carbon right there is going to

0:04:22.440,0:04:24.630
be bonded to the oxygen.

0:04:24.630,0:04:26.680
It's going to be bonded[br]to an oxygen, which

0:04:26.680,0:04:28.890
is bonded to a hydrogen.

0:04:28.890,0:04:32.530
Now, when you have a situation[br]like this, the oxygen will

0:04:32.530,0:04:34.990
have a partial negative[br]charge.

0:04:34.990,0:04:38.080
The hydrogen will still have[br]a partial positive charge.

0:04:38.080,0:04:40.180
Just like we saw up[br]here with both the

0:04:40.180,0:04:42.050
water and the methanol.

0:04:42.050,0:04:43.670
But now you have this big thing

0:04:43.670,0:04:45.260
here that has no polarity.

0:04:45.260,0:04:49.660
So this part of the alcohol is[br]not going to be soluble in

0:04:49.660,0:04:52.640
water, and it's going to make it[br]harder for this part to be

0:04:52.640,0:04:54.090
soluble over here.

0:04:54.090,0:04:57.130
So this right here[br]is less soluble.

0:04:57.130,0:04:58.210
This is less soluble.

0:04:58.210,0:04:59.730
It'd still be a little[br]bit soluble.

0:04:59.730,0:05:02.190
So if you have some oxygen here,[br]you will still have a

0:05:02.190,0:05:03.890
little bit of the hydrogen[br]bonding.

0:05:03.890,0:05:05.740
You still will have a little[br]bit of the hydrogen

0:05:05.740,0:05:06.360
bonding going on.

0:05:06.360,0:05:09.250
But this part is kind of-- you[br]can imagine it's almost-- it

0:05:09.250,0:05:11.370
doesn't want to dissolve[br]with the water.

0:05:11.370,0:05:12.620
It is non-polar.

0:05:12.620,0:05:14.900


0:05:14.900,0:05:17.110
You could actually, for[br]example, butanol in

0:05:17.110,0:05:19.700
particular, it actually[br]is soluble in water.

0:05:19.700,0:05:21.280
But not in any proportion.

0:05:21.280,0:05:23.800
So methanol is miscible.

0:05:23.800,0:05:24.390
Let me write this.

0:05:24.390,0:05:25.210
This is a new word.

0:05:25.210,0:05:27.530
I don't think I've ever used[br]it before in the context of

0:05:27.530,0:05:29.650
the organic chemistry videos.

0:05:29.650,0:05:32.660
So methanol is-- let me write[br]that in a brighter color since

0:05:32.660,0:05:34.360
it's a new word.

0:05:34.360,0:05:40.270
Methanol is miscible, which[br]just means soluble in any

0:05:40.270,0:05:41.520
proportion.

0:05:41.520,0:05:47.450


0:05:47.450,0:05:51.240
So I don't care what percent[br]is methanol,

0:05:51.240,0:05:53.140
what percent is water.

0:05:53.140,0:05:55.950
The methanol will dissolve[br]into the water in any

0:05:55.950,0:05:58.100
proportion.

0:05:58.100,0:06:01.380
If you look at butanol, it[br]is soluble but not in any

0:06:01.380,0:06:01.910
proportion.

0:06:01.910,0:06:04.900
If you had a ton of butanol,[br]some of it would not dissolve

0:06:04.900,0:06:05.660
in the water.

0:06:05.660,0:06:07.750
So this is soluble.

0:06:07.750,0:06:12.150
So the butanol right here[br]is soluble, but

0:06:12.150,0:06:18.430
not miscible in water.

0:06:18.430,0:06:20.940
If you have too much of the[br]butanol, all of a sudden, some

0:06:20.940,0:06:24.930
of it will not actually be[br]able to be dissolved.

0:06:24.930,0:06:28.460
If this was a decanol or[br]something with a really long

0:06:28.460,0:06:30.150
carbon chain, then of[br]course, it's going

0:06:30.150,0:06:32.290
to be very non soluble.

0:06:32.290,0:06:34.030
You might be able to get a[br]couple of molecules in the

0:06:34.030,0:06:36.600
water, but most of them[br]will not dissolve.

0:06:36.600,0:06:38.940
Now the other reason-- I[br]hinted-- look, you know the

0:06:38.940,0:06:42.260
reason why the alcohols have a[br]reasonable-- not too low of a

0:06:42.260,0:06:43.580
boiling point is that[br]they're able to do

0:06:43.580,0:06:44.930
this hydrogen bonding.

0:06:44.930,0:06:45.840
But you would say well, look.

0:06:45.840,0:06:47.970
You know, these longer carbon[br]chains, these are going to

0:06:47.970,0:06:50.140
have less of the hydrogen[br]bonding going on.

0:06:50.140,0:06:52.230
Maybe these would have[br]lower boiling points.

0:06:52.230,0:06:54.680
But actually, the longer the[br]chain gets, these actually

0:06:54.680,0:06:56.210
have higher boiling points.

0:06:56.210,0:06:57.830
And that's because[br]these chains can

0:06:57.830,0:06:59.780
interact with each other.

0:06:59.780,0:07:05.930
So the longer the chain, so[br]longer R or the longer R

0:07:05.930,0:07:08.800
chain, I guess, I could say,[br]we could say the higher the

0:07:08.800,0:07:10.620
boiling point in an alcohol.

0:07:10.620,0:07:12.420
Higher boiling point.

0:07:12.420,0:07:13.280
It's harder.

0:07:13.280,0:07:16.840
You have to put more heat into[br]the system or the temperature

0:07:16.840,0:07:18.860
has to be higher for the[br]things to break apart.

0:07:18.860,0:07:22.000
And that's because this is one[br]decanol molecule here, another

0:07:22.000,0:07:25.100
decanol molecule might[br]look like this.

0:07:25.100,0:07:26.950
Maybe it might look like this.

0:07:26.950,0:07:29.460
You have an oxygen and a[br]hydrogen and then you have

0:07:29.460,0:07:31.420
your carbons.

0:07:31.420,0:07:38.990
So you have your CH,[br]your CH2, CH2, H3C.

0:07:38.990,0:07:40.290
So you have this other[br]butanol here.

0:07:40.290,0:07:44.090
And what the interaction between[br]these two chains are--

0:07:44.090,0:07:46.090
these are the van[br]der Waal forces.

0:07:46.090,0:07:47.950
So even though they have[br]no [INAUDIBLE],

0:07:47.950,0:07:50.380
so these guys are going to have[br]some polar interactions.

0:07:50.380,0:07:51.650
They're going to have the[br]hydrogen bonding.

0:07:51.650,0:07:53.610
We've seen that multiple[br]times already.

0:07:53.610,0:07:57.250
But these long chains, they're[br]going to have the London

0:07:57.250,0:08:00.020
dispersion forces, which are a[br]subset of van der Waal forces.

0:08:00.020,0:08:02.840
Where even though they're[br]neutral, every now and then,

0:08:02.840,0:08:05.790
one of these might become[br]slightly negative on one side.

0:08:05.790,0:08:09.410
So you might have[br]a very temporary

0:08:09.410,0:08:10.670
partial negative charge.

0:08:10.670,0:08:13.370
And that's just because[br]of the randomness of

0:08:13.370,0:08:14.720
how electrons move.

0:08:14.720,0:08:18.110
On this side of the molecule,[br]all of a sudden, you might

0:08:18.110,0:08:19.630
have more electrons[br]over there.

0:08:19.630,0:08:21.460
So you have a partial[br]negative charge.

0:08:21.460,0:08:24.220
And because of that, you're[br]going to have-- the electrons

0:08:24.220,0:08:26.395
over here, they're not going[br]to want to be there.

0:08:26.395,0:08:28.210
So you're going to want to have[br]a partial positive charge

0:08:28.210,0:08:30.570
there and you're going to have[br]a very temporary interaction.

0:08:30.570,0:08:31.910
That's a very weak force.

0:08:31.910,0:08:33.880
Much weaker than[br]hydrogen bonds.

0:08:33.880,0:08:36.720
But as these chains get longer[br]and longer, as they possibly

0:08:36.720,0:08:38.840
even get intertwined with each[br]other and get close to each

0:08:38.840,0:08:42.230
other, these London dispersion[br]forces or van der Waal forces

0:08:42.230,0:08:43.220
are going to keep propagating.

0:08:43.220,0:08:44.970
So all of a sudden, maybe these[br]guys are going to be

0:08:44.970,0:08:46.900
attracted to each other and[br]that's going to disappear.

0:08:46.900,0:08:48.790
Than these guys are going be[br]attracted to each other and

0:08:48.790,0:08:50.000
then that's going[br]to disappear.

0:08:50.000,0:08:51.800
And then these are going to be[br]attracted to each other and

0:08:51.800,0:08:53.000
then that's going[br]to disappear.

0:08:53.000,0:08:54.940
And so you can imagine, the[br]longer the chain, the more of

0:08:54.940,0:08:57.290
these type of interactions[br]you're going to have. The more

0:08:57.290,0:08:58.970
attracted they're going[br]to be to each other.

0:08:58.970,0:09:01.720
And it's going to be harder to[br]break them apart, higher

0:09:01.720,0:09:02.680
boiling point.

0:09:02.680,0:09:04.810
So those are just kind of the[br]two big takeaways on the

0:09:04.810,0:09:08.350
properties of alcohols.

0:09:08.350,0:09:11.170
Especially smaller chained[br]alcohols are soluble in water.

0:09:11.170,0:09:13.610
The very small ones are[br]completely miscible.

0:09:13.610,0:09:16.026
And the longer the chain you[br]have, the harder it is to

0:09:16.026,0:09:16.870
dissolve in water.

0:09:16.870,0:09:19.130
But also, the higher[br]the boiling point.

0:09:19.130,0:09:20.940
The harder it is to break them[br]apart because you have these

0:09:20.940,0:09:23.180
London dispersion forces.

0:09:23.180,0:09:23.399