Question

In the equation PbO2 + 4HCl → 2H2O + PbCl2 + Cl2, how many electrons are transferred?

a. 1
b. 2
c. 3
d. 4

Answer 1

d. 4 IS WRONG! I took the test

Answer 2

Answer: The correct answer is Option b.

Step-by-step explanation:

To determine the number of electrons transferred, we need to first determine the half cell reactions.

For the given chemical reaction:

`PbO_2+4HCl\rightarrow 2H_2O+PbCl_2+Cl_2`

Lead is getting reduced because its oxidation state is changing from +4 to +2. Chlorine is getting oxidized because its oxidation state is changing from -1 to 0.

The half cell reactions for the above equation are:

Oxidation half reaction:
`2Cl^-\rightarrow Cl_2+2e^-`

Reduction half reaction:
`Pb^(4+)+2e^-\rightarrow Pb^(2+)`

From the above half reactions, total number of electrons transferred will be two.

Hence, the correct answer is Option b.