Question

Bromine can be liberated from potassium bromide solution by the action of?
(A) Iodine solution
(B) Chlorine water
(C) Sodium chloride
(D) Potassium iodide

Answer 1

Hint: In order to solve this question, you need to know the concept of oxidizing agents and then figure out which is a stronger oxidizing agent than bromine. Now try to figure out the answer by yourself.

Complete step by step answer:
As we know bromine is an element that exists in group seven and it occurs in various states, which include gas and liquid. It is a reddish-brown liquid which is used in areas such as agricultural chemicals, dyestuff, insecticides and chemical intermediates etc.

Let us see how bromine can be liberated.
When chlorine is bubbled into a solution of potassium bromide, it turns into bright red color, because bromide ions are oxidized to elemental bromide. This is how bromine is manufactured.
The balanced equation would be:

${ Cl }_{ 2 }+2KBr\longrightarrow { Br }_{ 2 }+2KCl$

Now, as we already know that chlorine solution is used in the process, but let us first understand the reason behind it.
Let us first understand the concept of electronegativity,
Electronegativity refers to the ability of an atom to attract shared electrons in a covalent bond.
As we know chlorine has a huge size and needs just one electron to fill its valence shell and be stable, because of larger size, the nucleus exerts a stronger pull on electrons. This stronger pull translates into a higher electronegativity for atoms in the same row of periodic table.

Therefore, Chlorine can replace bromine or chlorine can oxidize bromine. Hence, option B is the required answer.

Note: Remember that iodine solution cannot replace bromine, as we have already seen that Br is more reactive than iodine. So, Br can displace iodine, but Iodine cannot displace Br.