Question

4.what is exothermic reaction?which of the following is an exothermic reaction
a. Heating calcium carbonate and adding water to calciumoxide
b.aqeous solution of sodium chloride sodium sulphate and calcium chloride are taken in 3 separate test tube using aqueous barium chloride how do you identify sodium sulphate
c. Copper when exposed to air for a long time squires a green coat white​

Answer 1

Answer:

exothermic reaction is a chemical reaction in which heat is released.option (a)

Answer 2

Answer:

yar you have printed your whole book