Answer 1

Gibbs energy depends on the amount of substance. Hence it is an extensive property. However the electrical potential is independent of the amount of substance and thus, it is an intensive property.
eg. Consider a situation when the amount of substance is doubled. This can be done by multiplying the stoichiometric equation of redox reaction by 2. Hence, the amounts of substances oxidized and reduced are doubled. Also ∆G° and the number of electrons transferred are doubled. 
So, the ratio

`E^@=-(DeltaG^@)/(nF)` , becomes

`E^@=-(2DeltaG^@)/(2nF)=-(DeltaG^@)/(nF)`

Thus, E° remains constant.
Hence, electrical potential is an intensive property.