Question

What is the product formed when benzene is heated with acetic anhydride and anhydrous ${\text{AlC}}{{\text{l}}_{\text{3}}}$?
A.Acetophenone
B.Toluene
C.Benzoic acid
D.Phenyl acetic acid

Answer 1

Hint: Acetophenone: When aceto group i.e. $ - COC{H_3}$ is attached to the benzene then the resultant molecule is known as acetophenone.
Toluene: When only methyl group i.e. $C{H_3}$ is attached to the benzene then the resultant molecule is known as toluene.

Complete step by step solution:
First of all let us know about the compounds like acetophenone, toluene, benzoic acid and phenyl acetic acid.
Acetophenone: When aceto group i.e. $ - COC{H_3}$ is attached to the benzene then the resultant molecule is known as acetophenone.
Toluene: When only methyl group i.e. $C{H_3}$ is attached to the benzene then the resultant molecule is known as toluene.
Benzoic acid: When carboxylic acid group $ - COOH$ is attached to the benzene ring then the formed molecule is known as benzoic acid.
Phenyl acetic acid: When acetic acid group i.e. $ - C{H_2}COOH$ is attached to a benzene ring then the formed molecule is known as phenyl acetic acid.
Ortho position: In a benzene ring when two groups or atoms are at position $1,2$ i.e. at adjacent positions, are known as ortho positions. For example: if groups are nitro groups and they placed at position $1,2$ then they are said to be ortho nitro benzene.
Meta-position: In benzene rings when two or more groups or atoms are alternate to each other i.e. $1,3$ or $1,5$ positions, is known as meta-position. For example: if groups are nitro and they are placed at $1,3$ or $1,5$ positions then they are said to be meta nitro benzene.
Para-position: In a benzene ring when two or more groups or atoms are at opposite positions i.e. $1,6$, is known as para-position. For example: if groups are nitro and they are placed at $1,6$ positions then they are said to be para nitro benzene.
Now, when benzene is heated with acetic anhydride and anhydrous ${\text{AlC}}{{\text{l}}_{\text{3}}}$ then acetophenone is formed. This reaction is known as Friedal craft acylation reaction. The reaction is as:
${{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{ + C}}{{\text{H}}_{\text{3}}}{\text{COOCOC}}{{\text{H}}_{\text{3}}}\xrightarrow{{{\text{anhydrous AlC}}{{\text{l}}_{\text{3}}}}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{COC}}{{\text{H}}_{\text{3}}}{\text{ + C}}{{\text{H}}_{\text{3}}}{\text{COOH}}$. Hence option A is correct.

Note: There are many named reactions. For example: wittig reaction, Grignard reaction( which is used to form alkanes), Cannizaro reaction, Aldol reaction(confirm the presence of ketone group in the compound),etc. If these types of reactions are there then write the product directly.