Question

IUPAC name of $CH \equiv C - CH = C{H_2}$ is:
A.But-3-en-1 yne
B.But-1-en-3-yne
C.But-1-yn-3-ene
D.But-3-yn-1-ene

Answer 1

Hint:The parent carbon chain consists of 4 carbon atoms and is attributed by the suffix But followed by the type of bond present in the molecule , these are the thumb rules commonly followed and the IUPAC nomenclature rules are also followed in naming a particular compound.

Complete step by step answer:
The International Union of Pure and Applied Chemistry (IUPAC) have given a certain set of rules for the nomenclature of the compounds in order to name the compounds. Following are the main rules to be followed while naming the compound:
- The longest carbon chain is identified and is known as the parent chain.
- All the substituent groups are identified.
- The carbon atom is numbered in such a way that in the parent chain the substituents are given the lowest numbers.
- The location of each point on which the substituent occurs is given if the same substituent is present at more than one location.
- The number of times the substituent group occurs is indicated by a prefix (di, tri, tetra, etc.) for the numbers 2, 3, 4 etc.
- Only the prefix is used when the substituents are arranged in the alphabetical order.
- The chain having the greatest number of side chains is given the preference and is regarded as the parent chain.
- The prefix cyclo is used for the cyclic hydrocarbons.
Keeping in mind the above rules the Name of the compound is given as:
4 carbon atoms are there in the parent chain of the compound, with one double and one triple bonds in the chain. Priority is given to double bond over the triple bond when both the bonds are at the same position. The numbering will begin with the side where the double bond is present. Thus the IUPAC name of the compound is But-1-en-3-yne.

Note:
The rules given by the IUPAC are universal and the compound named through this system is known universally by the same name. Thus the name of the compound does not change and remains the same in the field of chemistry.