Assertion : Ag+/Ag increases with increase in concentration of Ag+ ions.
Reason : Ag+/Ag has a positive value.
(ii) Both assertion and reason are true and the reason is not the correct explanation of assertion.
Ag+(aq) + e- → Ag(S) E° = + 0.80 V, i.e., positive radox potential
According to the Nernst equation,
At 25°C,
Ecell = 
- 0.059 log 
(For, n=1)
= 
- 0.059 log 
(Since, molar concentration of an element in the solid state is equal to one, because the ratio of their density to their molar mass remains the same throughout the reaction)
= 
+ 0.059 log[Ag+]
We know, 
for Ag+/Ag couple is fixed. Thus, with increase in Ag+ concentration, i.e., [Ag+], log[Ag+] increases. Thus, Ecell value also increases.
Hence, EAg+/Ag increases with increase in concentration of Ag+ ions.