This is an incomplete question, the complete question is attached below.
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://tex.z-dn.net/?f=Ag%5E%2B%28aq%29%2BAl%28s%29%5Crightarrow%20Ag%28s%29%2BAl%5E%7B3%2B%7D%28aq%29)
The oxidation-reduction half reaction will be :
Oxidation : ![Al\rightarrow Al^{3+}+3e^-](https://tex.z-dn.net/?f=Al%5Crightarrow%20Al%5E%7B3%2B%7D%2B3e%5E-)
Reduction : ![Ag^{+}+1e^-\rightarrow Ag](https://tex.z-dn.net/?f=Ag%5E%7B%2B%7D%2B1e%5E-%5Crightarrow%20Ag)
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://tex.z-dn.net/?f=3Ag%5E%2B%28aq%29%2BAl%28s%29%5Crightarrow%203Ag%28s%29%2BAl%5E%7B3%2B%7D%28aq%29)
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.