Describe the differences between anode and cathode reactions in a voltaic cell.

Anode and cathode reactions in a voltaic cell differ in their electron transfer and electrode polarity.

In a voltaic cell, the anode is the electrode where oxidation occurs, and the cathode is the electrode where reduction occurs. At the anode, the metal or ion loses electrons and becomes oxidized, while at the cathode, the metal or ion gains electrons and becomes reduced. This electron transfer creates a flow of electrons from the anode to the cathode, generating an electric current.

The anode reaction is characterized by the loss of electrons and the production of cations, which move towards the cathode through the electrolyte. For example, in a zinc-copper cell, the anode reaction is: Zn(s) → Zn2+(aq) + 2e-. The zinc metal loses two electrons and forms zinc ions, which move towards the cathode.

The cathode reaction is characterized by the gain of electrons and the production of anions, which move towards the anode through the electrolyte. For example, in a zinc-copper cell, the cathode reaction is: Cu2+(aq) + 2e- → Cu(s). The copper ions gain two electrons and form copper metal, which deposits on the cathode.

Overall, the anode and cathode reactions in a voltaic cell are complementary and necessary for the generation of electrical energy. The anode provides the electrons, while the cathode accepts them, and the flow of electrons creates a potential difference that can be harnessed for useful work.