Question

Read the following chemical equations.

Answer 1

Answer:

D. Chlorine is reduced in reaction 1 and iron is oxidized in reaction 2.

Step-by-step explanation:

One way to determine if a substance has been oxidized or reduced is to calculate its oxidation number.

The important rules for oxidation numbers are:

1. The oxidation number of an element is zero.
2. The oxidation number of H is usually +1.
3. The oxidation number of Cl is usually -1.
4. The sum of all the oxidation numbers in a compound is zero.

Also,

• An increase in oxidation number is oxidation.
• A decrease in oxidation number is reduction.

$1. \stackrel{\hbox{+1}}{\hbox{H}_{2}}\stackrel{\hbox{-2}}{\hbox{S}} + \stackrel{\hbox{0}}{\hbox{Cl}}_{2} \longrightarrow\stackrel{\hbox{+1}}{\hbox{ 2H}}\stackrel{\hbox{-1}}{\hbox{Cl}} +\stackrel{\hbox{0}}{\hbox{S}}$

$2. \stackrel{\hbox{0}}{\hbox{Fe}} + \stackrel{\hbox{0}}{\hbox{S}} \longrightarrow \stackrel{\hbox{+2}}{\hbox{ Fe}}\stackrel{\hbox{-2}}{\hbox{S}}$

Thus, the oxidation number of S in H₂S and FeS is +2.

In Reaction 1, the oxidation number of Cl decreases from 0 to -1. The Cl is reduced.

In Reaction 2, the oxidation number of Fe changes from 0 to +2. The Fe is oxidized.