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) : [tex]Cr(s) \rightarrow Cr^{3+}(aq) + 3e^{-}[/tex] ...... (1)
At cathode (Reduction) : [tex]Ag^{+}(aq) + 1e^{-} \rightarrow Ag(s)[/tex]
So, in order to balance the half cell reactions, we multiply reduction reaction by 3. Hence, reduction reaction equation will be as follows.
[tex]3Ag^{+}(aq) + 3e^{-} \rightarrow 3Ag(s)[/tex] ........ (2)
Therefore, overall reaction will be sum of equations as (1) + (2). Thus, net reaction equation is as follows.
[tex]Cr(s) 3Ag^{+}(aq) \rightarrow Cr^{3+}(aq) + 3Ag(s)[/tex]