What type of reaction is shown below?

2Na + 2H2O?2NaOH + H2 + heat

A. nuclear

B. exothermic

C. endothermic

D. spontaneous

An exothermic reaction is a type of chemical reaction in which energy is released to the environment in form of heat or light. Endothermic reaction in the other hand is a chemical reaction where energy is taken from the surroundings and thus the surroundings end up with less energy than they started with. In this case; the above reaction is an Exothermic reaction (heat is being released to the surroundings).