Video Transcript
Which molten salt would produce
sodium metal and chlorine gas when electrolyzed? (A) MgCl2, (B) NaCl, (C) NaBr, (D)
NaF, or (E) AlCl3.
If something has been electrolyzed,
it has undergone electrolysis. Electrolysis is a chemical process
where electricity is passed through an electrolyte, causing it to decompose into its
constituent elements. Electrolysis occurs in an
electrolytic cell. A positively charged anode exists
on one side, and a negatively charged cathode exists on the other. It is hooked up to a dc power
supply because alternating current won’t work if we want to collect decomposition
products.
Salts are ionic compounds and can
dissociate into their constituent ions. The negative ions are attracted to
the anode, and the positive ions are attracted to the cathode. During the process of electrolysis
in an electrolytic cell, the cations, or positive ions, will be reduced and the
anions, or negative ions, will be oxidized.
For us to isolate sodium metal and
chlorine gas from an electrolysis reaction, there needs to be sodium and chlorine
ions present in our salt. The only answer choice which
contains both sodium and chloride ions is sodium chloride. Thus, the molten salt that would
produce sodium metal and chlorine gas when electrolyzed is (B), NaCl.
