Video Transcript
The following equation describes the base hydrolysis of ethyl acetate, where the X-term represents an unidentified liquid. CH3COOC2H5 liquid plus NaOH aqueous react to produce CH3COONa aqueous plus X liquid. What is the structure of the unidentified liquid?
X, an unidentified liquid, is one of the products of the base hydrolysis of ethyl acetate. Looking at the chemical formula of ethyl acetate, we see COO. This group can be referred to as the ester link and helps us to identify ethyl acetate as an ester. Now that we know that ethyl acetate is an ester, we need to understand what happens to esters when they undergo base hydrolysis. Hydrolysis is defined as a chemical reaction where water reacts with a compound, breaking one or more bonds. Although base hydrolysis is classified as a hydrolysis reaction, a strong base is used as the reactant instead of water. Although water isn’t used as the reactant in base hydrolysis, the reaction still involves the breaking of one or more bonds.
Let’s take a closer look at the base hydrolysis of a generic ester. In this reaction, the carbonyl carbon single bond to oxygen is broken. An alcohol is produced from the alkoxy group, and a carboxylate salt is formed. Here’s the same reaction equation using only chemical formulas. From the chemical formula, we can see that the base hydrolysis of an ester separates the ester link.
With this in mind, let’s take another look at ethyl acetate. We know that during base hydrolysis of an ester, the ester link will be broken. We’ve seen that the portion of the ester which contains the carbonyl carbon will become a part of the carboxylate salt. The remaining portion of the ester, the alkoxy portion, will become the alcohol. So unidentified liquid X is an alcohol with the chemical formula C2H5OH. But the question asks for the structure of X. Looking at the chemical formula, we see that X contains one oxygen atom. This means we can eliminate answer choices (A), (C), and (D) as they do not contain the correct number of oxygen atoms.
Compound X also contains six total hydrogen atoms. From this information, we can eliminate answer choice (E) as this structure only contains four hydrogen atoms. This leaves us with answer choice (B), the structure of a two-carbon alcohol. So the structure of unidentified liquid X, which is the alcohol produced via the base hydrolysis of ethyl acetate, is the structure shown in answer choice (B).
