Answer : The coefficient of silver in the final, balanced equation for this reaction is, 3
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
The given redox reaction is,
![Ag^+(aq)+Al(s)\rightarrow Ag(s)+Al^(3+)(aq)](https://img.qammunity.org/2020/formulas/chemistry/high-school/kfhv8iabqdy1ba0ox5kgj3tjzkktuy4knd.png)
The oxidation-reduction half reaction will be :
Oxidation :
![Al\rightarrow Al^(3+)+3e^-](https://img.qammunity.org/2020/formulas/chemistry/college/yom0fq0dufw7qoo0wvq3a6mx4pgss2nvth.png)
Reduction :
![Ag^(+)+1e^-\rightarrow Ag](https://img.qammunity.org/2020/formulas/chemistry/college/smzzrsgsfuihwfp9qp1ubui5iek9xffk8x.png)
In order to balance the electrons, we multiply the reduction reaction by 3 and then added both equation, we get the balanced redox reaction.
The balanced redox reaction will be,
![3Ag^+(aq)+Al(s)\rightarrow 3Ag(s)+Al^(3+)(aq)](https://img.qammunity.org/2020/formulas/chemistry/high-school/9p6g4sb53tkgp52j5ndqh7ouyx031ryefb.png)
From the balanced redox reaction we conclude that, the coefficient of silver in the final balanced equation for this reaction is 3.
Hence, the correct option is 3.