Question

Draw the following incorrectly named compounds and name them correctly.

a.2-ethyl-3-methyl-5-isopropylhexane

b.2-ethyl-4-tert-butylpentane

c.3-methyl-4-isopropylpentane

d.2-ethyl-3-butyne

Short answer

The correct names are

a. 3-ethyl- 2,4,5-trimethylheptane

b. 2,2,3,5-tetramethylheptane

c. 2,3,4 -trimethylhexane

d. 3-methylpent- 1-yne

Step-by-step solution

To draw the structure of alkanes

The first step in determining the correct name is drawing structures of alkanes from the given name.

Names of organic molecules have three parts: the base name, the suffix, and the prefix.

The base name tells us how many carbons are in the longest continuous carbon chain.

The suffix tells us what functional group is present.

The prefix is pinpointing which, where and how much substituents we have attached to the carbonchain.

Naming organic molecules

After drawing the structure of each given alkane, we must follow simple steps for naming organic molecules.

1) Find the longest continuous carbon chain.

The number of carbons in the longest continuous chain gives us the base name.

2) The second step is adding the suffix to the parent name.

For alkanes, the suffix is ane.

3) Next step is to number the atoms in the continuous carbon chain to give all the substituents the lowest possible numbers.

4) After assigning numbers to carbon atoms, and therefore to the substituents, we need to name the substituents

Name and position of the substituents gives us the prefix

5) The final step is to combine the prefix with the parent name and the suffix.

(It is important that you do not forget to alphabetize the names of the substituents)

2-ethyl-3 -methyl-5 -isopropylhexane

a.After drawing the structure for 2-ethyl-3-methyl-5-isopropylhexane we can see that the longest carbon chain was not chosen.

2,2,3,5-tetramethylheptane

b. Again, the longest carbon chain was not chosen. After following the rules listed above, you get the correct name, 2,2,3,5-tetramethylheptane.

 3-methyl-4-isopropylpentane

c. The correct name for the drawn molecule is 3-methyl-4 -isopropylpentane. This way, all substituents have the smallest number on the longest continuous carbon chain.

To Draw the carbon chain

d. The longest continuous carbon chain has five C atoms