Video Transcript
Which of the following equations
represents the electrolysis of water? (A) H2O liquid makes H2 gas plus O2
gas. (B) two H2O liquid makes two H2 gas
plus O2 gas. (C) H2O liquid makes H+ aqueous
plus OH− aqueous. (D) two H2 gas plus O2 gas makes
two H2O liquid. (E) two H2O liquid makes two OH−
aqueous plus H2 gas.
Electrolysis is a chemical process
where electricity is passed through an electrolyte, causing it to decompose into its
constituent elements. This process uses an electrolytic
cell and a dc power supply. To sustain an electrolytic
reaction, electrodes and an electrolyte solution are required to complete the
circuit. We need to be able to continuously
get power from the battery or power supply, which means that the ions in our
solution need to be able to move.
The mobility of ions is typically
achieved by keeping our electrolyte solution liquid. In the case of a salt electrolyte,
the solid salt is heated to its melting point, to ensure a liquid state. Another common way to ensure ion
mobility of salts is to dissolve them in water. However, when electrolyzing a
solution like this, water itself can be electrolyzed. The electrolysis of water is the
process by which water is decomposed into oxygen and hydrogen gas using electric
current and can be represented by the following equation.
So which of our answer choices
matches this equation? Only answer choices (A) and (B)
have reactants and products that match. So we can eliminate the rest from
consideration. As we can see, only answer choice
(B) has the same molar ratio as our initial equation. Therefore, answer choice (B) is
correct. Two H2O liquid makes two H2 gas
plus O2 gas is the correct answer.
