Answer:
Will be doubled.
Explanation:
For a capacitor of parallel plates of area A, separated by a distance d, such that the charges in the plates are Q and -Q, the capacitance is written as:
where e₀ is a constant, the electric permittivity.
Now we can isolate V, the potential difference between the plates as:
Now, notice that the separation between the plates is in the numerator.
Thus, if we double the distance we will get a new potential difference V', such that:
So, if we double the distance between the plates, the potential difference will also be doubled.