Video Transcript
Which of the following is true upon the reaction of ethanol with sodium metal? (A) Formation of sodium ethoxide with the evolution of hydrogen gas. (B) Formation of sodium ethoxide with the evolution of carbon dioxide gas. (C) Formation of sodium acetate with the evolution of hydrogen gas. (D) Formation of sodium acetate with the evolution of carbon dioxide gas. Or (E) formation of sodium ethoxide with the evolution of carbon monoxide gas.
This question is asking us about the reaction of ethanol with sodium metal. The name ethanol ends in O-L, which indicates that ethanol is an alcohol. When an alcohol is reacted with sodium metal, the hydrogen is removed from the hydroxy group, producing a negatively charged ion called an alkoxide. At the same time, sodium metal is oxidized to sodium ions, producing a sodium alkoxide. When this process occurs to two alcohol molecules, the removed hydrogen atoms can combine to form hydrogen gas, which bubbles off of the reaction. Each answer choice involves the evolution of a gas. But since we know that hydrogen gas is a product of the reaction between an alcohol and sodium metal, we can eliminate answer choices (B), (D), and (E).
To decide between answer choices (A) and (C), let’s take a look at the specific reaction between ethanol and sodium metal. We already know that ethanol is an alcohol and contains a hydroxy group. Eth- indicates that the molecule contains two carbon atoms, and A-N indicates that the atoms are single bonded together. From the information provided in the name, we can draw this structure for ethanol.
We know that when two molecules of an alcohol react with sodium metal, the hydrogen atoms are removed and combine to form hydrogen gas. The sodium is oxidized and a sodium alkoxide is produced. We can name this particular sodium alkoxide by removing the prefix alk- and replacing it with a prefix that indicates the number of carbon atoms in the alkoxide. The alkoxide contains two carbon atoms, so we use the prefix eth-. Thus, the sodium alkoxide produced via this reaction is sodium ethoxide. So the statement that is true upon the reaction of ethanol with sodium metal is (A) formation of sodium ethoxide with the evolution of hydrogen gas.
