Answer: c. condensation of ethanol vapor
Explanation: An endothermic reaction is a type of of chemical reaction in which energy is absorbed from the surrounding. The temperature of the surrounding decreases.
An Exothermic reaction is a type of of chemical reaction in which energy is released into the surrounding. The temperature of the surrounding increases.
a.boiling of water: This involves conversion of liquid to gas and thus require energy and is endothermic.
b.melting of copper: This involves conversion of solid to liquid and thus require energy and is endothermic.
c. condensation of ethanol vapor: This involves conversion of vapor to liquid and thus release energy and is exothermic.
d.sublimation of iodine: This involves conversion of solid to gas and thus require energy and is endothermic.