Question

What amount of bromine will be required to convert $2g$ of phenol into $2,4,6 -$ tribromophenol?
A. $4.0$
B. $6.0$
C. $10.2$
D. $20.4$

Answer 1

We need to know that the phenol is an aromatic compound having the chemical formula ${C_6}{H_5}OH$. And this compound contains one phenyl ring which makes a bond with one hydroxyl group. When the phenol is reacted with bromine, it will attack on the second, fourth and sixth position of the phenol. The required amount of bromine can be found by using the molecular weight of bromine and the phenol.

Complete answer:
As we know, the bromine required for$2g$of phenol into $2,4,6 -$tribromophenol is not equal to $4.0$. Hence, option (A) is incorrect.
The amount of bromine not equal to $6.0$. Hence, option (B) is incorrect.
Here, the bromine is reacted with phenol, the bromination reaction will occur and there is a formation of $2,4,6 -$tribromophenol. Here, the bromine attacks the second, fourth and sixth position of the phenol. Here, the solvent is bromine and it has a great influence on the reaction. The chemical reaction of bromine and phenol can be written as,

The molecular mass of phenol $= 12 \times 6 + 1 \times 6 + 16 = 94$
The molecular weight of the bromine $= 3 \times 160 = 480$
Amount of bromine required for $94g$ phenol $= 480g$
Therefore, amount of bromine required for $2g$ phenol$= \dfrac{{480}}{{160}} \times 2 = 10.22g$
Hence, option (C) is correct.
The bromine required to convert $2g$ of phenol is not equal to $20.4$. Hence, the option (D) is incorrect.

So, the correct answer is “Option C”.

Note:
By the reaction of phenol and bromine, there is a formation of $2,4,6 -$ tribromophenol and this reaction is known as bromination reaction. Here the bromine will attack the phenol. The bromine is a highly stabilized ionic solvents. Therefore, there is a formation of a strong ortho – para directing group and the stabilization of bromine ions will increase the formation of $2,4,6 -$ tribromophenol.