Video Transcript
Which of the following statements
about the reaction of phenol with sodium metal is correct? (A) It produces sodium phenoxide
and oxygen gas. (B) It produces benzene and sodium
hydroxide. (C) It produces sodium phenoxide
and hydrogen gas. (D) It produces benzene and sodium
hydride. (E) It produces sodium phenoxide
and sodium hydroxide.
In this question, we are given the
reactants of a chemical reaction, which are phenol and sodium metal. Phenol is an organic molecule
consisting of a hydroxy or OH group directly bonded to an aromatic ring. Sodium metal is an alkali metal and
is considered a very reactive metal. In order to determine which of the
statements is true about the chemical reaction, it would be helpful to predict the
products of this reaction by writing a chemical equation.
Let’s begin by writing the chemical
formulas of the reactants. The molecular formula of phenol is
C6H5OH, and the chemical symbol for sodium metal is Na. Phenol is a weak acid. In general, acids tend to react
with reactive metals such as sodium to produce a new compound and hydrogen gas. Phenol is acidic enough to react
with sodium metal, so we know one of the products of the reaction will be hydrogen
gas, which has the chemical formula H2. But what will the other product
be?
During the reaction, each sodium
metal atom loses an electron to form a sodium cation. This means the sodium metal was
oxidized. In a chemical reaction, when a
chemical species is oxidized, typically another chemical species is reduced. During the reaction, each phenol
molecule releases a hydrogen ion from the hydroxy group, leaving behind an
anion. These hydrogen ions accept the
electrons given off by the sodium atoms and combine to form hydrogen gas. The oppositely charged ions left
behind combine to form a new compound, which has the name sodium phenoxide.
Now let’s write the chemical
formula for sodium phenoxide. It is C6H5O−Na+. Finally, to complete our balanced
equation, we’ll place a coefficient of two in front of phenol, sodium, and sodium
phenoxide. So there we have it; when phenol
reacts with sodium metal, sodium phenoxide and hydrogen gas are produced. Therefore, the statement that is
correct about the reaction of phenol with sodium metal is “It produces sodium
phenoxide and hydrogen gas,” or answer choice (C).
