To 50 g of water at 00C is added 20 g of ice at 00C. What will be the mass of water that will freeze or ice that will melt?
No ice will melt ; nor will any water freeze
Since ice and water are bot at 0oC, it is a state of Thermal Equilibrium, and therefore no heat will be exchanged between them. Thus no ice will melt, nor will any water freeze.