Question

In potassium bromide solution, chlorine displaces.
A) Bromide.
B) Iodide.
C) Chloride.
D) Fluoride.

Answer 1

We know that a displacement reaction is the one in which the atom or a group of atoms is displaced by another atom in a molecule. For Example, if iron is added to a solution of copper sulphate the iron displaces the copper metal.
$A{\text{ }} + {\text{ }}B - C{\text{ }} \to {\text{ }}A - C{\text{ }} + {\text{ }}B$
In the above equation A and B have to be either Halogen where C indicates a cation.

Complete step by step answer:
We know that bromine is less reactive than chlorine so if chlorine is added to potassium bromide solution, the chlorine ion replaces bromine and forms potassium chloride solution. The displacement of bromine can be detected by the color change. We can write the chemical equation for the given as,
$2KBr + C{l_2} \to 2KCl + B{r_2}$

So, the correct answer is Option A .

Additional Information:
If chlorine is added to a solution of sodium bromide, the bromine is displaced by chlorine. Because bromine is less reactive than the bromine so it displaces bromine from sodium bromide. Then the solution turns brown and the color change indicates the displaced bromine. The chlorine has gone to form sodium chloride.
$Chlorine{\text{ }} + {\text{ S}}odium{\text{ }}bromide{\text{ }} \to {\text{ S}}odium{\text{ }}chloride{\text{ }} + {\text{ B}}romine$
In this equation, the Chlorine and Bromine have swapped places.
This type of displacement reaction happens with all the halogens.

Note:
We must remember that the halogens in the solutions of their salts are displaced by the most reactive halogen, and is itself displaced by none of the others and the least reactive halogen displaces does not replace any other atoms, and it is displaced by itself by the other entire atom in the solution.