Question

Assertion: Sulpha drugs contain sulfonamide group:
Reason: Salvarsan is a sulpha drug:
A ) Both assertion and reason are correct and reason is the correct explanation for assertion.
B ) Both assertion and reason are correct but reason is not the correct explanation for assertion.
C ) Assertion is correct but reason is incorrect.
D ) Both assertion and reason are incorrect.

Answer 1

Hint: Any drug that contains sulfonamide functional group is called sulfa drug. Sulfonamide functional group is \[ - {\text{S}}{{\text{O}}_{\text{2}}}{\text{NHR}}\] group. Sulfonamide is the amide of benzene sulphonic acid. It is obtained by introducing \[ - {\text{NHR}}\] in place of \[ - {\text{OH}}\] group of \[ - {\text{S}}{{\text{O}}_{\text{2}}}{\text{OH}}\] group of benzene sulphonic acid.

Complete answer:
The sulfonamide functional group is \[ - {\text{S}}{{\text{O}}_{\text{2}}}{\text{NHR}}\]. Sulphonamides are structurally similar to PABA. PABA is para amino benzoic acid.
Examples of sulphonamide include sulfadiazine and sulfamethoxazole.

Sulfa drugs are also known as sulfonamides. These drugs consist of several synthetic antibiotics, which possess the sulfonamide functional group in their molecules. Hence, the assertion is correct.
Paul Ehlrich was a German bacteriologist.
For the treatment of syphilis, it was necessary to produce a substance which has less toxicity. To achieve this objective, Paul Ehlrich studied Arsenic based structures and developed the arsphenamine. Arsphenamine is a medicine , which is also called salvarsan. Salvarsan is not a sulfa drug as it does not contain sulfonamide functional groups. Salvarsan contains a double bond between two arsenic atoms. It has two benzene rings in its structure. Each benzene ring has one amino substituent and one phenolic hydroxyl group as substituent. Salvarsan drugs are usually given in the form of hydrochloride salt.

Thus, the option C ) is the correct answer.

Note: Sulfa drugs are used for the treatment and prevention of infections caused by the bacteria. Thus they are bacteriostatic. They are wide spectrum antibiotics and are effective against gram positive and gram negative bacteria.