Question

In an acid-base neutralization reaction 38.74 M, which of the following is an oxidation-reduction reaction?

a) Pb(C_2H_3O_2)2(aq) + 2 KBr(aq) → PbBr_2(s) + 2 KC_2H_3O_2(aq)
b) Ca(s) + 2 HBr(aq) → CaBr_2(aq) + H_2(g)
c) KI(aq) + AgNO_3(aq) → AgI(s) + KNO_3(aq)
d) HCl(aq) + LiOH(aq) → LiCl(aq) + H_2O(l)

Answer 1

In the given reactions, only (b) Ca(s) + 2 HBr(aq) → CaBr2(aq) + H2(g) represents an oxidation-reduction reaction because there is a transfer of electrons, indicated by the change in oxidation states.

Step-by-step explanation:

The student question pertains to recognizing an oxidation-reduction reaction within a neutralization context. Neutralization typically refers to acid-base reactions where H+ ions from the acid and OH- ions from the base combine to form water. However, certain reactions can involve a transfer of electrons, which characterizes an oxidation-reduction reaction.

Analysis of the reactions:

(a) Pb(C2H3O2)2(aq) + 2 KBr(aq) → PbBr2(s) + 2 KC2H3O2(aq) - This reaction does not involve a change in the oxidation states of the ions involved, thus it is not an oxidation-reduction reaction.

(b) Ca(s) + 2 HBr(aq) → CaBr2(aq) + H2(g) - Calcium goes from 0 to +2 oxidation state and hydrogen goes from +1 to 0. This is an oxidation-reduction reaction since there is a transfer of electrons.

(c) KI(aq) + AgNO3(aq) → AgI(s) + KNO3(aq) - Like (a), no changes in oxidation states, thus not an oxidation-reduction reaction.

(d) HCl(aq) + LiOH(aq) → LiCl(aq) + H2O(l) - This is a typical acid-base neutralization with no change in oxidation states.