Question

How many of the following are oxidation-reduction reactions?

NaOH + HCl → NaCl + H₂O,
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂,
Mg(OH)₂ → MgO + H₂O,
N₂ + 3H₂ → 2NH₃

Answer 1

In the given reactions, the second and fourth reactions are oxidation-reduction reactions. The first and third reactions are not oxidation-reduction reactions because there is no change in the oxidation states of the elements.

Step-by-step explanation:

Oxidation-reduction reactions involve a transfer of electrons between reactants. In the given reactions:

1. NaOH + HCl → NaCl + H₂O: This reaction is not an oxidation-reduction reaction because there is no change in the oxidation states of the elements.
2. Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂: This reaction is an oxidation-reduction reaction. Copper (Cu) is oxidized because its oxidation number increases from 0 to +2, and silver (Ag) is reduced because its oxidation number decreases from +1 to 0.
3. Mg(OH)₂ → MgO + H₂O: This reaction is not an oxidation-reduction reaction because there is no change in the oxidation states of the elements.
4. N₂ + 3H₂ → 2NH₃: This reaction is an oxidation-reduction reaction. Nitrogen (N₂) is reduced because its oxidation number decreases from 0 to -3, and hydrogen (H₂) is oxidized because its oxidation number increases from 0 to +1.