Q1: Molar heat capacity of water in equilibrium with ice at constant pressure is

ANS:B - ∞

The molar heat capacity of water in equilibrium with ice at constant pressure is not any of the options provided. At the phase equilibrium between water and ice, the temperature remains constant as heat is absorbed by the ice to melt it while the water releases the same amount of heat to freeze back into ice. This process occurs at the melting point of ice, which is 0∘𝐶0∘C (or 273.15273.15 K) at standard atmospheric pressure. The molar heat capacity (𝐶𝑝Cp​) is defined as the amount of heat required to raise the temperature of one mole of a substance by one degree Celsius at constant pressure. For water, its molar heat capacity varies with temperature. However, at the phase equilibrium between water and ice, the temperature remains constant, and thus, the molar heat capacity at this point is undefined. So, none of the options provided (0, ∞, 1) accurately represents the molar heat capacity of water in equilibrium with ice at constant pressure.