Alcohols can act either as weak acids or as weak bases, just as water can. Show the reaction of

Alcohols can act either as weak acids or as weak bases, just...

Key Concepts

Deprotonation Reaction

A deprotonation reaction involves the removal of a proton from a molecule by a base, resulting in the formation of its conjugate base. When methanol reacts with a strong base, the strong base abstracts a proton from the hydroxyl group, leading to the production of an alkoxide ion and the corresponding conjugate acid of the base.

Acid-Base Chemistry

Acid-base chemistry is a central topic in chemistry that involves the transfer of protons (hydrogen ions) between chemical species. This area of study is essential for understanding how various substances react in aqueous solutions, particularly focusing on how acids donate protons and bases accept them.

Amphoteric Nature

The amphoteric nature of a substance refers to its ability to act as both an acid and a base. Water is a classic example, and similarly, alcohols like methanol can donate or accept a proton depending on the reacting agent, showcasing their dual behavior in acid-base reactions.

Protonation Reaction

A protonation reaction occurs when a molecule containing a lone pair of electrons accepts a proton from an acid, forming its conjugate acid. In the context of methanol reacting with a strong acid, the oxygen atom in methanol accepts a proton from the acid to yield a protonated alcohol species.

Transcript

00:01 They tell us alcohols can act either as weak acids or weak bases, and they want us to show the reaction of methanol with a strong acid, like hydrochloric acid, as well as sodium amid, which is a strong base.

00:18 So in this first case, methanol is going to be acting as a base, since they were telling us that hydrochloric acid is going to be our strong acid, and we should recall that from general chemistry as well.

00:31 So let's go ahead and actually draw how this will react.

00:35 So the only thing with lone pairs and our methanol is going to be that alcohol right there, or the oxygen on the alcohol.

00:43 So what's going to end up happening is, so let me draw this bond going between these.

00:52 One of the lone pairs from the oxygen is going to come over here, still that hydrogen.

00:57 And now this hydrogen doesn't like having the two bonds.

01:00 So it's going to break the bond between the hydrogen and the chlorine, and the bond is going to go to the chlorine here.

01:08 So let's go ahead and actually draw the lone pairs on that chlorine as well.

01:12 So we should end up with, so we have the alcohol, and it's going to have two hydrogens attached to it now.

01:23 One of its lone pairs went to steal that hydrogen, so that means it's going to have one lone pair now.

01:29 And if we were to check out the formal charge for this, it would have a positive charge because it would have 1, 2, 3, 4, 5 electrons in its failance.

01:38 It normally has 6, so it essentially lost one.

01:42 Now for the chlorine, it had 3 loan pairs, so 1, 2, 3.

01:49 It gained one from that bond, so it has 4.

01:52 Now chlorine is going to have 8 electrons.

01:55 It normally has 7, so this is going to have a negative charge.

01:58 All right.

01:59 Now what about when it reacts with sodium amid? so remember, this nitrogen here is going to have two lone pairs on it...