Current is applied to an aqueous solution of calcium sulfide. Multiple choice help please??!

What is produced at the cathode?
A) H2(g)
B) S(s)
C) O2(g)
D) Ca(s)

What is produced at the anode?
A) O2(g)
B) H2(g)
C) Ca(s)
D) S(s)

4 answers

I don't know about the over voltage associated with these ions. Over voltage not withstanding, H2 at the cathode and O2 at the anode. S(s) (from S^2-) is VERY close.
H2 (g) is produced at the cathode. S (s) is produced at the anode. Just compare reduction potentials.
H2 (g) at cathode
S (s) at anode
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