Assertion: A room can be cooled by opening the door of a refrigerator in a closed room.
Reason: Heat flows from lower temperature (refrigerator) to higher temperature (room).
When the door of refrigerator is kept open, heat rejected by the refrigerator to the room will be more than the heat taken by the refrigerator from the room (by an amount equal to work done by the compressor). Therefore, temperature of room will increase and so it will be warmed gradually. As according to 2nd law of thermodynamics, heat cannot be transferred on its own, from a body at lower temperature to another at higher temperature.