Question

The IUPAC name of the following compound is:

(A) Propane-1,2,3-tricarbonitrile
(B) 3-Cyanopetane-1,5-dinitrile
(C) Pentane-1,3,5-trinitrile
(D) All

Answer 1

Hint: Steps to write the IUPAC name of a compound:
1. Identify the functional group (it can be alcohol, aldehyde, ether etc.).
2. Find the longest carbon chain.
3. Number of carbon atoms present in the longest chain.
4. If there is any branched group, identify their position and name them.
5. Combine the elements' names in a single word.

Complete step by step solution:
* -CN group is named as carbonitrile when they are supposed to yield carboxylic acid on hydrolysis in an aliphatic chain,
* The longest carbon chain here is propane that means 3 carbon, and with each carbon there is one -CN group attached.
* So, the branched CN groups are on the position 1,2,3 and they are three in number. So, we will write ‘tri’ before carbonitrile.
* As we know, the compounds are named in an alphabetical order, thus, propane will be written first.
* Therefore, the IUPAC name of the following compound propane-1,2,3-tricarbonitrile. Its molecular formula is \[{{C}_{6}}{{H}_{5}}{{N}_{3}}\], also the condensed formula is \[CNC{{H}_{2}}CHCNC{{H}_{2}}CN\].
So, the correct option is (a).

Note: Carbon atoms of the terminal groups are not counted in the principal chain. If any one of the terminal groups is not directly attached to the parent chain and forms the part of the side chain, then the longest chain is selected containing two such similar groups at its two ends. The groups present in the side chain are treated as substituents and are indicated by suitable prefixes.