Question

IUPAC system of $CC{{l}_{3}}-CHO$ called:
A. Chloral
B. $1,1,1$- trichloroethanal
C. $2,2,2$-trichloroethanal
D. Trichloroacetaldehyde

Answer 1

IUPAC stands for International Union of Pure and Applied Chemistry. IUPAC system of naming compounds is the internationally accepted system which is accepted everywhere uniformly.

Complete step by step answer:
The IUPAC system is internationally accepted everywhere to ease the communication and provide a standard.
Other than IUPAC names compounds have a common name which varies from place to place like from country to country.
The main aim of IUPAC naming is to give each compound a unique name so that we can easily differentiate between them also so that when new compounds are added they can be named according to that system.
It is very difficult to remember the names of all the compounds so we use this system so that we can name any compound any time anywhere without much botheration.
According to the IUPAC naming system priority is given to that chain of carbon which has the largest number of carbon atoms in it and numbering is started where there is a functional group.
Different functional groups have different prefixes and suffixes. Prefix and suffix are also dependent on the number of atoms of carbon.
In the given question, aldehyde is the primary group and hence it’s carbon will get the first number and the other carbon second which goes like ${{C}^{2}}(C{{l}_{3}})-{{C}^{1}}(HO)$ and hence it will be named as $2,2,2$- trichloroethanal.

hence option C is correct.

Note: Here, chlorine atoms are inside the chain of the second carbon thrice so the number $2$ is written thrice according to the IUPAC system of naming.