Longest chain rule: Select the longest continuos chain of carbon atoms. This is called the parent chain while all other carbon atoms which are not included in the parent chain are called branch chain or side chains or substituent.it may be noted that the longest chain may or may not be straight but it must be continuous. 2) Rule for larger number of side chain : If two … [Read more...] about Rules for IUPAC nomenclature of Branched chain alkanes