Question

Sodium carbonate extract of bromide and iodide in addition to ______ (A) and ____ (B) gives brown or violet layer to (A). (A) and (B) are:
A.Chloroform and bromoform
B.Chloroform and iodoform
C.$CHCl_3$ and chlorine
D.$CHCl_3$ and bromine

Answer 1

This reaction is mainly performed in the laboratories. It involves the use of salt solution, further it will be neutralized with an acid. We can say that the presence of chloroform layer can change the colour in addition to salt solution.

Complete step by step answer:
Now, we have to find out the chemical or substance added to the sodium carbonate extract of bromide and iodide.
-As we know when the salt solution like NaCl is shaken with chloroform, or chlorine water. We will observe a change of layer.
-We will see that the chloroform layer obtained in the solution has turned violet.
-Now, if we add a little amount of chloroform $CHCl_3$ and excess amount of chlorine water to sodium carbonate extract as discussed in the case of salt solution.
-We have to perform this reaction with the help of a shaking tube. So, after the addition, neutralize it with an acid like HCl and shake it.
-Here, we will observe the change of colour in the formed layer.
-Thus, we can say that the colour attained will be violet.
-In the last, we can conclude that the presence of chloroform, and chlorine gives brown or violet colour to the extract.
Hence option (C) is the correct answer.

Note:
This reaction is performed to confirm the presence of iodide or bromide ions by the change of colour in laboratories. As in this case the addition of chloroform changes the colour to violet and brown. The violet colour confirms the presence of iodide ions whereas brown colour confirms the presence of bromide ions.