Identify which substances are oxidized and which are reduced for the following reaction. Provide answers through steps by step

Question

Zn + 2HCl = H2 + ZnCl

Answer 1

2

Step 1: Write the oxidation numbers for each element in the reactants and products:

Zn: 0
H: +1 (in HCl and H2)
Cl: -1 (in HCl and ZnCl2)

Step 2: Determine how the oxidation numbers change from reactants to products.

Zn goes from 0 to +2, a loss of electrons. This means Zn is oxidized.
H goes from +1 to 0, a gain of electrons. This means H is reduced.
Cl goes from -1 to 0, a gain of electrons. This means Cl is reduced.

Step 3: Write the half-reactions showing the oxidation and reduction separately:

Oxidation half-reaction:
Zn -> Zn2+ + 2e-

Reduction half-reaction:
2H+ + 2e- -> H2

Step 4: Check that the number of electrons lost in the oxidation half-reaction is equal to the number of electrons gained in the reduction half-reaction.

The oxidation half-reaction loses 2 electrons, while the reduction half-reaction gains 2 electrons. They balance each other out.

Therefore, Zn is oxidized and H and Cl are reduced in the reaction:
Zn + 2HCl -> H2 + ZnCl2