6.When hydrochloric acid is poured on limestone, the mixture fizzes, releasing a colorless, odorless gas. The equation for this chemical reaction is located below. What is the identity of the gas?CaCO3(s) + 2 HCl(aq) ---> CaCl2(aq) + CO2(g) + H2O(l)Select one:a. CaCl2b. CaCO3c. CO2d. H2O