Question

A student is asked to balance an equation by using the half-reaction method. He determines the two half reactions as shown below.

2Br- ➡️ Br2+2e-
Cl2+2e-➡️2Cl-

What should he write as the final, balances equation ?

Cl2 +2Br-➡️Br2+2Cl-
Cl2+2Br-+2e-➡️Br2+2Cl-
Cl2+2Br-➡️Br2 +Cl- + 2e-
Cl2 +Br-+2e-➡️Br2+Cl-+2e-

Answer 1

2Br ⁻ ➡️ Br2+2e-

Cl2+2e-➡️2Cl⁻

Cl2 +2Br⁻➡️Br2 +2Cl⁻

Answer A.

Answer 2

Answer: The correct answer is
`Cl_2+2Br^-\rightarrow Br_2+2Cl^-`

Step-by-step explanation:

Net ionic equation is defined as the equation in which total number of electrons exchanged are equal.

We are given two half reactions, out of which one is oxidation half reaction and other is reduction half reaction.

Oxidation half reaction:
`2Br^-\rightarrow Br_2+2e^-`

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

The net ionic equation for the above reactions will be:
`Cl_2+2Br^-\rightarrow Br_2+2Cl^-`

Hence, the correct answer is
`Cl_2+2Br^-\rightarrow Br_2+2Cl^-`