Use of Carb- Prefix before functional group names?

[Ansuman]

1. I have been facing problem with the use of carb-prefix under same special conditions in organic chemistry nomenclature.

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3. One friend of mine suggested me that if there are 3 or more similar functional group, out of which none can be given priority in a single structure, then usually carb- prefix is used before the secondary suffix like tricarbamide, tricarbaldehyde, and so on. To provide further clarity to my question , the image has been given below.
First image is named 1,3,-Pentanedioic Acid

Second image is named 1,2,3-Tricarboxylic Acid

Also it will be very kind, if you can suggest me onto which are the specific conditions , no single functional group(out of similar multiple ones in a structure), be given priority so that they are left out of parent chain and treated as substituents

 

[Asim Riaz]

, and carb- prefix is used. The specific conditions for when carb- prefix should be used vary depending on the context and the type of functional group involved. Generally, carb- prefix should be used when there are three or more identical functional groups in a single structure and none of them can be given priority over the others. This may occur when all the functional groups are terminal, none of them have substituents attached, or if they have the same number of substituents attached. For example, 1,3-pentanedioic acid has two carboxylic acid groups with different priorities, so the "dioic" suffix is used instead of "tricarboxylic". However, 1,2,3-tricarboxylic acid has three carboxylic acid groups that all have the same priority, so the "tricarboxylic" suffix is used.