Video Transcript
Which of the following equations
outlines the reaction used in industry to produce large quantities of ethyne? (A) Four CO2 gas plus two H2O
liquid react to form two C2H2 gas plus five O2 gas. (B) C2H4 gas reacts to form C2H2
gas plus H2 gas. (C) Two CHI3 solid plus six Ag
solid react to form C2H2 gas plus six AgI solid. (D) CH3CHO liquid reacts to form
C2H2 gas plus H2O liquid. (E) Two CH4 gas reacts to form C2H2
gas plus three H2 gas.
First of all, ethyne is an alkyne,
which is an unsaturated hydrocarbon with at least one carbon–carbon triple bond. Ethyne is the simplest alkyne and
is composed of only two carbon atoms and two hydrogen atoms. Ethyne can be made in the lab using
calcium carbide and water. Let’s write a balanced chemical
equation for this reaction.
The reaction happens spontaneously
when calcium carbide is added to water, releasing ethyne gas. The reaction also produces the
by-product calcium hydroxide. The reaction is not efficient on a
large scale because for every one gram of ethyne produced, 2.8 grams of calcium
hydroxide are also produced.
The alternative method to producing
ethyne that is typically used in industry is the partial combustion of methane. At high temperatures, methane gas
can react to produce ethyne gas and hydrogen gas. Let’s write a balanced chemical
equation to represent this reaction. The product ethyne must be
separated from the product mixture before it can be used.
When looking at the answer choices,
we can see that answer choice (E) matches the chemical equation that we wrote. In conclusion, the equation that
outlines the reaction used in industry to produce large quantities of ethyne is
answer choice (E): two CH4 gas reacts to form C2H2 gas plus three H2 gas.
