Question

Carbolic acid is [AFMC $2005$]
A.${{C}_{6}}{{H}_{5}}CHO$
B.${{C}_{6}}{{H}_{6}}$
C.${{C}_{6}}{{H}_{5}}COOH$
D.${{C}_{6}}{{H}_{5}}OH$

Answer 1

Hint: Carbolic acid is an aromatic and volatile crystalline compound. As it is mildly acidic and it can cause chemical burns, we should handle it very carefully. In aqueous medium carbolic acid loses one proton and thus gains stability due to the delocalization of negative charge throughout the aromatic ring.

Complete answer:Carbolic acid is an organic aromatic acid as it contains a phenyl group bonded to a $-OH$. Phenol is often called carbolic acid. So, the chemical formula of carbolic acid is the same as phenol. That is ${{C}_{6}}{{H}_{5}}OH$. Thus the structures of carbolic acid can be drawn in the following ways:



Here in this structure, we can see a $-OH$group is attached to benzene via a single bond. This alcoholic $-OH$group creates a partial positive charge on the hydrogen atom and a partial negative charge on the oxygen atom and due to the high electronegativity of oxygen facilitates the breaking of this polar $O-H$bond, thereby losing one ${{H}^{+}}$ion to form the most stabilized resonance structures which can be shown in below:


 Carbolic acid is an older name for phenol or hydroxy benzene with the chemical formula ${{C}_{6}}{{H}_{5}}OH$.
Thus, option (D) is correct.

Note: Carbolic acid is one of the oldest antiseptic agents. It is widely used in the household to prevent snake infestation and is a versatile precursor to a large collection of drugs for example aspirin as well as many other pharmaceutical herbicides and drugs. Carbolic acid also has many commercial applications for the production of plastics, polycarbonates, epoxides, etc.