Which of the following will give a positive carbylamine test? 1\. \(\mathrm{H}_{3} \mathrm{C}-\mathrm{NH}_{2}\) 2\. \(\mathrm{H}_{3} \mathrm{C}-\mathrm{NH}-\mathrm{CH}_{3}\) 3\. \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}\) 4\. \(\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{NH}_{2}\) Select the correct answer using the codes given below. (a) 1 and 3 (b) 2 and 4 (c) 1 and 4 (d) 3 and 4

Primary amines are organic compounds that consist of a nitrogen atom bonded to one alkyl or aryl group and two hydrogen atoms. This structure is denoted as RNH2 where R represents an alkyl or aryl group. Their simplicity in structure is key in differentiating them from secondary and tertiary amines, which have the nitrogen atom linked to two or three alkyl or aryl groups, respectively.

When it comes to qualitative tests in organic chemistry, primary amines are unique in that they undergo the carbylamine reaction. This reaction forms a distinctively pungent-smelling isocyanide, serving as a clear and unequivocal identification method. Understanding the structural makeup and reactivity of primary amines is crucial for correctly interpreting results from qualitative tests like the carbylamine test.

Qualitative analysis in organic chemistry involves determining the presence or absence of particular functional groups in a molecule. It employs various chemical tests that produce observable changes, such as color shifts, precipitates, or, as with the carbylamine test, odor changes.

The carbylamine test, for instance, is designed specifically to identify primary amines. As a qualitative test, it does not provide quantitative data or concentration levels but offers a 'yes' or 'no' answer to the presence of this functional group. When performing the test, a positive result, indicated by the creation of a foul smell, allows for a rapid assessment and differentiation of primary amines from other amine types. Knowing how to interpret such qualitative tests is essential for students and chemists in identifying unknown substances in a mixture or confirming the presence of specific functional groups.

Amines are a class of organic compounds characterized by the presence of a nitrogen atom bonded to hydrogen atoms, alkyl, or aryl groups. The amine functional group is broadly categorized into primary, secondary, and tertiary amines, dictated by the number of carbon-containing groups attached to the nitrogen atom.

Primary amines have one carbon-containing group, secondary amines have two, and tertiary amines have three. Each type of amine has distinct properties and reactivities, which is why they respond differently to tests such as the carbylamine test. Understanding these functional groups is fundamental to grasping the basics of organic chemistry and is crucial for effective communication and problem-solving within the field.