Question

When ice melts, the change in internal energy is greater than the heat supplied. Why ?

Answer 1

When ice melts, volume of water formed is less than that of ice. So, surroundings (environment) does work on the system (ice). 

And by first law, 

∆Q = ∆ W + ∆U 

∆U = ∆Q - ∆ W (∆ W= negative as work is done on the system) 

∆U > ∆Q