What are reasonable values for the position of an airplane's center of gravity compared to that of its center of lift? I understand that if the center of gravity is in front of neutral point, it is stable. If the center of gravity is behind the neutral point, it is unstable. Based on the diagram, is it implied that h (center of gravity) cannot be greater than 1? When h = 1, there will only be c (mean aerodynamic chord). What does it mean if h>1? Is it off the wing basically?



hnwb = 0.25 (typically)

When I solved a problem, my h value was greater than 1. Isn't that incorrect because it is off the wing?
If I understand your question correctly, h is a fraction of mean aerodynamic chord c. That fraction can be >1. It could be that the aircraft is stable with a huge download on the tail.

The mean aerodynamic chord is an aid, to simplify calculations. It is not a hard limit for the equilibrium points. Whether the value is reasonable or not is hard to say without having seen the full problem to be solved.