Look at the combination reaction below. Use the rules to assign oxidation numbers to each element in the reaction. Choose the 4 statements below that are TRUE of the reaction.

Question

P4+10Cl2-->4PCl5

a
The oxidation number of Chlorine (Cl) decreases.
b
The oxidation number of Chlorine (Cl) increases.
c
The oxidation number of Phosphorous (P) increases.
d
The oxidation number of Phosphorous (P) decreases.
e
Chlorine (Cl) undergoes oxidation.
f
Chlorine (Cl) undergoes reduction.
g
Phosphorous (P) undergoes reduction.
h
Phosphorous (P) undergoes oxidation.

Answer 1

The oxidation numbers for each element in the reaction are as follows:

P4: Each P atom has an oxidation number of 0.
Cl2: Each Cl atom has an oxidation number of 0.
PCl5: Each P atom has an oxidation number of +5, and each Cl atom has an oxidation number of -1.

Based on these oxidation numbers, the true statements are:

c. The oxidation number of Phosphorous (P) increases.
e. Chlorine (Cl) undergoes oxidation.
g. Phosphorous (P) undergoes reduction.
f. Chlorine (Cl) undergoes reduction.