Question

What is molecular formula for 3 - Ethyl - 2, 3 - dimethyl pentane

Answer 1

Rules for IUPAC Nomenclature:-

(1) Recognize the functional group in the compound. That will determine the suffix of the name.

(2) Find the longest continuous chain length that contains the functional group and count the number of carbon atoms in the chain. The number will determine the prefix.

(3) Number the carbon in the longest chain. You need to start numbering so that the functional group is on the carbon with lowest possible number. Start with the carbon at the end closest to the functional group.

(4) Look for only branched group:-

$⟶$ Name them by counting the number of carbon atom in the branched group.

$⟶$ Note the position of the group on the main carbon chain. If there is more than one same type of branched group then both numbers must be listed e.g: $(2,4-)$ and one of the prefixes must be used.

$⟶$ The branched group must be listed before the name of the main chain in alphabetical order

Number Prefix-

$2$ di-

$3$ Tri-

$4$ Tetra-

$3-Ethyl-2,3-dimethylpentane$

$C{H}_3$ $C{H}_3$

$\underset{1}{H_{3}C}-\stackrel{|}{\underset{2}{CH}}-\stackrel{|}{\underset{|3}{C}}-\underset{4}{C{H}_2}-\underset{5}{C{H}_3}$

$C{H}_2-C{H}_3$