Question

Which of the following equations represent redox reactions? For each redox reaction, determine which atom is oxidized and which is reduced, and identify the oxidizing agent and the reducing agent.
a. MgO(s) + H2CO3(aq) → MgCO3(s) + H2O(l)
b. 2KNO3(s) → 2KNO2(s) + O2(g)
c. H2(g) + CuO(s) → Cu(s) + H2O(l)
d. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)
e. H2(g) + Cl2(g) → 2HCl(g)
f. SO3(g) + H2O(l) → H2SO4(aq)

Answer 1

Answer:

c. H2(g) + CuO(s) → Cu(s) + H2O(l)

e. H2(g) + Cl2(g) → 2HCl(g)

Explanation:

A redox reaction is a reaction that involves a changes in oxidation number of the species involved in the reaction.

The oxidizing agent experiences a decrease in oxidation number while the reducing agent experiences an increase in oxidation number.

For H2(g) + CuO(s) → Cu(s) + H2O(l)

Copper is reduced from +2 to 0 while hydrogen is oxidized from 0 to +2 Hence hydrogen is the reducing agent while copper is the oxidizing agent.

For H2(g) + Cl2(g) → 2HCl(g)

Chlorine is reduced from 0 to -1 while hydrogen is oxidized from 0 to +1. Hence chlorine is the oxidizing agent while hydrogen is the reducing agent.