Zinc acts as the anode and copper acts as the cathode in a voltaic cell. The assertion given in the question is incorrect. The correct option would be:

Assertion: In a voltaic cell, zinc acts as the anode and copper acts as the cathode.
Reason: The use of sulfuric acid makes the acidulated water behave as an electrolyte.

Explanation:
Voltaic cells, also known as galvanic cells, convert chemical energy into electrical energy through redox reactions. These cells consist of two half-cells connected by a conductive material, such as a wire. Each half-cell contains an electrode and an electrolyte.

Zinc acts as the anode in a voltaic cell, while copper acts as the cathode. The anode is the electrode where oxidation occurs, while the cathode is the electrode where reduction occurs. In this case, zinc undergoes oxidation, losing electrons to form Zn2+ ions. The copper ions from the solution gain these electrons and get reduced to form copper atoms, which are deposited onto the copper electrode.

The reason given in the question is incorrect. The use of sulfuric acid does not determine the roles of zinc and copper in the cell. Sulfuric acid, when added to water, dissociates into hydrogen ions (H+) and sulfate ions (SO4^2-). This mixture of sulfuric acid and water is commonly referred to as acidulated water and acts as the electrolyte in the cell.

The electrolyte allows the flow of ions between the two half-cells, completing the circuit and allowing the transfer of electrons from the anode to the cathode. In a voltaic cell, the electrolyte does not determine the roles of the electrodes. The roles are determined by the standard reduction potentials of the electrode materials, where the material with the higher reduction potential becomes the cathode, and the material with the lower reduction potential becomes the anode.

In conclusion, the correct option is that zinc acts as the anode and copper acts as the cathode in a voltaic cell. The use of sulfuric acid does not determine the roles of zinc and copper in the cell, but rather provides the electrolyte necessary for the flow of ions between the two half-cells.

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