Final answer:
The reactants for the neutralization reaction that produces H2O and CaCl2 are hydrochloric acid (HCl) as the acid, and calcium hydroxide (Ca(OH)2) as the base. Together, they undergo a neutralization reaction to form calcium chloride and water.
Step-by-step explanation:
A neutralization reaction typically involves the reaction of an acid and a base to produce water (H2O) and a salt. In the given reaction, water and calcium chloride (CaCl2) are the products. To produce these products, the reactants must be a source of H+ (an acid) and OH- (a base) ions.
Hydrochloric acid (HCl) is the acid because it is a source of H+ ions in solution. Calcium hydroxide (Ca(OH)2) is the base because it provides OH- ions. When these two substances react, they form CaCl2 and water:
HCl(aq) + Ca(OH)2(aq) → CaCl2(aq) + 2H2O(l)
The complete balanced equation of the neutralization reaction shows the acid-base combination that results in the desired products.