Why doesn't sulfuric acid react with electrowinning zinc at the cathode?

[SMD1990]

Zinc reacts with sulfuric acid to produce zinc sulfate and hydrogen. But then, when electrowinning zinc, this is reversed, with zinc deposited on the cathode, oxygen evolved at the anode, and sulfuric acid also produced.

So why does the sulfuric acid not immediately react with the zinc, negating the plating process? Does it have to do with the applied voltage somehow "holding off" the normal reaction?

 

[Borek]

So why does the sulfuric acid not immediately react with the zinc, negating the plating process? Does it have to do with the applied voltage somehow "holding off" the normal reaction?

Yes, once you switch off the voltage, zinc will dissolve.