Write structure for each of the following compounds. Why are the given names incorrect ? Write correct IUPAC names. (i) 2-Ethylpentane (ii) 5-Ethyl-3-methylheptane

Write structure for each of the following compounds. Why are the given

1.	Write structure for each of the following compounds. Why are the given names incorrect ? Write correct IUPAC names. (i) 2-Ethylpentane (ii) 5-Ethyl-3-methylheptane
Answer» Solution :(i) The STRUCTURE of 2-Ethylpentane : `CH_(3)-underset(C_(2)H_(5))underset(\|)(CH)-CH_(2)-CH_(2)-CH_(3)` Longest chain is of six carbon atoms and not that of five. Hence, correct name is 3-Mehylhexane. (ii) `overset(7)CH_(3)-overset(6)(CH_(2))-underset(CH_(3))underset(\|)overset(5)(CH)-overset(4)(CH_(2))-underset(C_(2)H_(5))underset(\|)overset(3)(CH)-overset(2)CH_(2)-overset(1)(CH_(3))` NUmbering is to be started from the end which gives LOWER number to ETHYL GROUP. Hence, correct name is 3-ethyl-5-methylheptane.