Answer to Question #229251 in Inorganic Chemistry for David Gio

Question

The enthalpy of vaporization of HF lower than C2. Explain with reason.

Answer 1

When heat is supplied to a solid (like ice) at a steady rate by means of an electrical heating coil, we find that the temperature climbs steadily until the melting point is reached and the first signs of liquid formation become evident, as can be seen on the graph below. Thereafter, even though we are still supplying heat to the system, the temperature remains constant as long as both liquid and solid are present. On the graph below, this is represented by the flat line, where energy is being added to the ice, but no change is occuring in the temperature. All energy added to the system at this stage is used to convert solid ice into liquid water.