Fill in the blanks:
$(i)$ If the molecules of a body repel each other,then the surface area ...... and the surface energy ...... (choose between 'increases' or 'decreases').
$(ii)$ If the molecules of a body attract each other,then the surface area ...... and the surface energy ...... (choose between 'increases' or 'decreases').

(A) Surface energy is defined as the work done in increasing the surface area of a liquid.
$(i)$ If molecules repel each other,the system tends to expand to minimize the potential energy associated with repulsive forces. Consequently,the surface area increases,and since work is done by the system to increase this area,the surface energy increases.
$(ii)$ If molecules attract each other,the system tends to contract to minimize potential energy. Consequently,the surface area decreases,and the surface energy decreases.