Consider Two Adjacent Water Molecules in an Ice Crystal

Consider two adjacent water molecules in an ice crystal. Assume that the binding energy connecting them follows a Lennard-Jones potential with a potential well depth of 9.6x10-21 J. How much energy must you put into the system to increase the separation of the two atoms by 10% from the equilibrium spacing?

A) 0.2x10-21 J
B) 0.4x10-21 J
C) 0.9x10-21 J
D) 1.8x10-21 J
E) 9.6x10-21 J