Question

Write balanced chemical reactions for each step in the two-step synthesis of calcium chloride. Next, write an overall reaction for the two-step synthesis of aqueous calcium chloride from calcium and hydrochloric acid. You can do this by subtracting one equation from the other. Your equations should include the details about state (s), (aq), (g), (l).

Answer 1

Answer:

For the first reaction: Ca (s) + Cl2 (g) ⇒ CaCl2

For second reaction: Ca (s) + 2HCl (aq) ⇒ CaCl2 (aq) + H2 (g)

Explanation:

1) First you have to write the equations that describes the synthesis of calcium chloride from calcium (Ca) and chlorine (Cl2). The overall reaction can be separated in two semi-reactions, the oxidation of calcium and the reduction of chlorine.

Ca (s) ⇒ Ca+2  + 2e- (oxidation)

Cl2 (g) + 2 e- ⇒ 2Cl-   (reduction)

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Ca (s) + Cl2 (g) + 2e- ⇒ CaCl2 (s) + 2e- (overall reaction)

Summarizing Ca (s) + Cl2 (g) ⇒ CaCl2

2) In the second part you must consider the reaction of Calcium and hydrochloric acid to form aqueous calcium chloride.

Ca (s) ⇒ Ca+2 + 2e-

2HCl (aq) ⇒ 2H+ (aq)  + 2Cl- (aq)

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Ca (s) + 2HCl (aq) ⇒ CaCl2 (aq) + H2 (g)