Two point charges of different magnitudes and of opposite signs are separated by some distance. There can be

E is a vector quantity;  V is a scalar quantity. 

On the line joining the charges , there must be a point ( not between the charges ) where electric field is zero .

Suppose +$Q_1 is at the origin and -Q_2 is at point (d,0).If the potential at point P(x,y)$ is zero , then 

 $\frac{k{Q}_1}{\sqrt{x^2+y^2}}-\frac{k{Q}_2}{\sqrt{{(d-x)}^2+y^2}}=0$.

All points on the curve given by the above equation must be at zero potential .