# Forming hydrogen sulfide from electrolysis of sodium thiosulfate

So I was doing electrolysis on two silver electrodes and sodium thiosulfate. Some observations

• The voltage drops extremely fast from 2 V to less than 1 V in 15 minutes, possibly because of the thiosulfate reduction.

• Gases are liberated out of solution.

• The solution turns black quickly.

Alert: I am using a fume hood.

Since I'm afraid of this spoiled eggs smell I just want to know if I am in any way creating hydrogen sulfide? Just want to be sure that the gas is tetrathionate and not hydrogen sulfide.

My other concern is with the voltage. How can I keep it from dropping so fast?

Render the thiosulfate ion as $(\ce {S-}-\ce {SO3-})$. Then at the cathode:
$(\ce {S-}-\ce {SO3-})+2e^- \rightarrow \ce {S^{2-}}+\ce {SO3^{2-}}$