Question

To prepare phenol from halobenzene, which process is useless?
A. Grignard
B. Raschig
C. Dow
D. Schiff

Answer 1

Hint: It is the reaction product of a dye formulation such as fuchsin and sodium bisulphite. It is also used as a qualitative test for aldehydes, as an unknown sample is added to its reagent if magenta color appears than aldehyde is present. This reagent is also used for biological tissue staining methods.

Complete step by step solution
In the Grignard reaction:
Grignard reagent is used to convert chlorobenzene into phenol by hydrolysis.
In the case of raschig process:
The Raschig process is also an industrial process for the production of phenol by chlorobenzene.
In case of Dow process:
In dow’s process, benzene gets easily converted into chlorobenzene by electrophilic aromatic substitution and after that hydrolysis is done to produce phenol.
In case of Schiff process:
Schiff reagent is the product of a dye formulation such as fuchsin and sodium bisulphite. It is also used as a qualitative test for aldehydes, as an unknown sample is added to its reagent if magenta color appears than aldehyde is present. This reagent is also used for biological tissue staining methods.
So, the Schiff process is useless for the conversion of halobenzene to phenol.
Hence, option D is correct.

Note
Ethers are also the organic compound that have an oxygen atom attached to two alkyl groups or aryl groups. General formulas of ethers are given as $ R - O - R' $ where $ R $ and $ R' $ are alkyl groups or aryl groups. Biologically ethers are the common linkage in carbohydrates and lignin. They are prepared by the dehydration of alcohol in the presence of concentrated sulphuric acid at $ 413K $ temperature.