[Single-digit Integer] A gas is confined in a graduated cylinder enclosed by a movable piston. When — States of Matter and Gaseous State Chemistry Question

Question

[Single-digit Integer] A gas is confined in a graduated cylinder enclosed by a movable piston. When the temperature of the room is 27°C, the volume of the gas at atmospheric pressure is found to be 45 ml. The cylinder is then immersed in a bath containing a mixture of liquid and solid benzene, maintained at the normal freezing point of benzene. The piston moves to maintain constant atmospheric pressure. The volume of the gas at the freezing point of benzene is 42 ml. The freezing point of benzene (in °C) is