Question

Classify the following reactions: HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l)HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l) Ba(OH)2(aq)+ZnCl2(aq)→BaCl2(aq)+Zn(OH)2(s)Ba(OH)2(aq)+ZnCl2(aq)→BaCl2(aq)+Zn(OH)2(s) 2AgNO3(aq)+Mg(s)→Mg(NO3)2(aq)+2Ag(s)

Answer 1

The reactions are

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s)

2AgNO3(aq) + Mg(s)  →  Mg(NO3)2(aq) + 2Ag(s)

Answer:

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)   =  Acid-base reaction

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s)  =  Precipitation reaction

2AgNO3(aq) + Mg(s)  →  Mg(NO3)2(aq) + 2Ag(s)  =  Redox reaction

Explanation:

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)  .

The reaction above is an example of an acid-base reaction. Acid-base reaction is a chemical reaction between an acid and a base. The product is usually a salt and water. An acid dissolves in water to produce H+ ion. Hydrochloric acid is a strong acid as it is completely dissociated in water. A base dissolves in water to form hydroxide ion(OH-). The sodium hydroxide is a strong base as it completely dissociate in water. The reaction between a base and an acid can be known as a neutralization reaction.

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s)

The reaction above is a precipitation reaction. Precipitation reaction is a reaction where two ionic bonds or cations and anions in an aqueous solution react to form an insoluble salts. The insoluble salt formed is known as the precipitate. The reaction above is an example of a double replacement reaction. From the equation the ions replace each other depending on the cations and anions. They switch partners as both reactants lose their partners to form new partnership with a different ion. The two reactants ( Ba(OH)2 and ZnCl2 ) are aqueous solution, they react to from a solid precipitates( Zn(OH)2(s) ).

2AgNO3(aq) + Mg(s)  →  Mg(NO3)2(aq) + 2Ag(s)

The reaction is known as an oxidation-reduction reaction(Redox reaction). A oxidation-reduction reaction their is a transfer of electron(s) between two species. The oxidation number of a chemical reaction changes by losing or gaining electrons. One of the reactant is a reducing agent and the other is an oxidizing agent.

From the reaction Mg is the reducing agent and AgNO3 is the oxidizing agents.

2 Ag+  +   2 e- → 2 Ag∧0  (reduction)

    Mg∧0  -  2 e- → Mg²+ (oxidation)