Question

The half-cell is a chamber in the voltaic cell where one half-cell is the site of the oxidation reaction and the other half-cell is the site of the reduction reaction. Type the half-cell reaction that takes place at the anode for the chromium-silver voltaic cell. Indicate the physical states of atoms and ions using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively. Use (aq) for an aqueous solution. Do not include phases for electrons. Express your answer as a chemical equation.

Answer 1

Explanation:

In a voltaic cell, oxidation reaction occurs at anode whereas reduction reaction occurs at the cathode.

Hence, the half-cell reaction taking place at anode and cathode will be as follows.

At anode (Oxidation) : $Cr(s) \rightarrow Cr^{3+}(aq) + 3e^{-}$ ...... (1)

At cathode (Reduction) : $Ag^{+}(aq) + 1e^{-} \rightarrow Ag(s)$

So, in order to balance the half cell reactions, we multiply reduction reaction by 3. Hence, reduction reaction equation will be as follows.

              $3Ag^{+}(aq) + 3e^{-} \rightarrow 3Ag(s)$  ........ (2)

Therefore, overall reaction will be sum of equations as (1) + (2). Thus, net reaction equation is as follows.

      $Cr(s) 3Ag^{+}(aq) \rightarrow Cr^{3+}(aq) + 3Ag(s)$