The following two half-reactions occur in a voltaic cell:Ni (s) Ni2 + (aq) + 2 e - (electrode = Ni) Cu2 + (aq) + 2 e - Cu (s) (electrode = Cu) Which one of the following descriptions most accurately describes what is occurring in the half-cell containing the Cu electrode and Cu2 + (aq) solution? (a) The electrode is losing mass and cations from the salt bridge are flowing into the half-cell. (b) The electrode is gaining mass and cations from the salt bridge are flowing into the half-cell. (c) The electrode is losing mass and anions from the salt bridge are flowing into the half-cell. (d) The electrode is gaining mass and anions from the salt bridge are flowing into the half-cell.

The electrode is gaining mass and cations from the salt bridge are flowing into the half-cell

Explanation:

In every voltaic cell, there are two half cells each with different electrodes and electrolytes. The both half cells are connected by a salt bridge which aids in maintaining charge balance between the half cells.

Oxidation occurs at the anode, this electrode decreases in mass and the amount of positive ions increases in this half cell. Anions flow from the salt bridge towards the anode half cell.

Reduction occurs at the cathode. Substances are deposited at the cathode and this electrode increases in mass. The cathode half cell soon become depleted of positive ions due to reduction reaction going on and cations from the salt bridge flow towards the cathode.

In the cell mentioned in the question, nickel functions as anode while copper functions as the cathode. The copper half cell increases in size and becomes depleted of Cu2 + ions. Cations flow from the salt bridge towards this half cell in order to maintain charge balance.