Question

A voltaic cell is assembled by using two 30-mL beakers. In one beaker, Ag metal is used as the electrode with 10 mL of 1 M AgNO3. In the other beaker, Zn metal is used as the electrode with 10 mL of 1 M ZnSO4. The beakers are connected with a salt bridge and the measured cell potential, Eocell, is 1.50 V. The Zn electrode is negative (anode). Which reaction takes place at the Zn electrode

Answer 1

Reaction that takes place at the Zn electrode is oxidation:

Zn ⇄ Zn²⁺ + 2e⁻

Step-by-step explanation:

This excersise explains the structure of a typical battery, that is useful to study electrochemistry.

AgNO₃ → Ag⁺ + NO₃

ZnSO₄ → Zn²⁺ + SO₄⁻²

Generally batteries contains 2 electrodes, where we have 2 conductive metallic. Batteries work to obtain electricity from a chemistry reaction which is always a redox type. One electrode releases electrons while the other catch them. Electrons travel from the anode to cathode, so in the anode, the e⁻ are released.

Reaction that takes place at the Zn electrode is oxidation:

Zn ⇄ Zn²⁺ + 2e⁻

Oxidation state is increased, electrons are free to go to cathode, where the other element decreases the oxidation state:

Ag⁺ + e⁻ ⇄ Ag

In the middle of the battery, the salt bridge (generally KCl) contributes the redox with more charges. Cl⁻ for the anode and K⁺ for the cathode.

Note that the same amount of electrons travel from anode to cathode, because in this example, Ag gained 1 mol and Zn released 2 moles.

The scheme for the battery is:

⁻ Zn(s) / Zn²⁺ (aq) // Ag⁺ (aq) / Ag (s) ⁺

1 M 1 M

Where the first place represents the anode, // represents the salt bridge and then, the cathode. Below, we write the molar concentration of each salt.