Question

Consider the following voltaic cell. Identify the anode and cathode, and indicate the direction of Na ion and NO3- ion flow from the salt bridge. A. Sn is the anode and Fe is the cathode; Na ions flow into half-cell compartment (A) and NO3- ions flow into half-cell compartment (B). B. Fe is the anode and Sn is the cathode; NO3- ions flow into half-cell compartment (A) and Na ions flow into half-cell compartment (B). C. Sn is the anode and Fe is the cathode; NO3- ions flow into half-cell compartment (A) and Na ions flow into half-cell compartment (B). D. Fe is the anode and Sn is the cathode; Na ions flow into half-cell compartment (A) and NO3- ions flow into half-cell compartment (B).

Answer 1

Answer:

Fe is the anode and Sn is the cathode; NO3- ions flow into half-cell compartment (A) and Na ions flow into half-cell compartment (B).

Explanation:

The purpose of a salt bridge in a voltaic cell is not to move electrons from the electrolyte, it's main function is the maintenance of charge balance between the half cells .The electrons flow from the anode to the cathode.

The iron half cell which has a higher reduction potential serves as anode. Iron atoms give up electrons to form positive ions according to the equation;

Fe(s)-----> Fe^2+(aq) + 2e

Hence there will be an excess of positive ions in the anode (compartment A). NO3^- ions from the salt bridge will migrate towards this compartment to ensure charge balance.

Similarly, in compartment B(cathode) Sn^2+ ions will accept two electrons according to the reaction;

Sn^2+(aq) + 2e ------> Sn(s)

This reaction causes a depletion of positive ions in compartment B, hence Na^+ from the salt bridge move towards this compartment to ensure charge balance.