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, balanced equation?

Answer 1

See,both oxidation and reduction half are already balanced,hence you simply add both the equation you will get the net reaction.

Answer 2

Answer: The final balanced equation for the two given half equations is $2Br^-(aq.)+Cl_2(g)\rightarrow Br_2(g)+2Cl^-(aq.)$

Explanation: We are provided with two half cell equations. One cell equation is taking place at anode and other at cathode.

At anode, oxidation reaction occurs which is when an element looses electrons and at cathode, reduction reaction takes place which is when an element gains electrons.

The final equation does not contain electrons because electrons gets cancelled out in the two half cell reactions. Hence,

At Anode:        $2Br^-(aq.)\rightarrow Br_2(g)+2e^-$

At Cathode:    $Cl_2(g)+2e^-\rightarrow 2Cl^-(aq.)$

Net Equation:  $2Br^-(aq.)+Cl_2(g)\rightarrow Br_2(g)+2Cl^-(aq.)$