What is wrong with the following names? Give the correct name for each compound. a. 2 -ethylpropane b. 5 -iodo \(-5,6\) -dimethylhexane c. cis-4-methyl-3-pentene d. 2 -bromo- 3 -butanol

The given name of the compound is 2-ethylpropane. First, locate the longest continuous chain of carbon atoms, which here is propane (3 carbons). Then, determine the position of the ethyl group (2 carbons) on the propane chain, which is at position 2. The compound does not make sense, since the ethyl group cannot be on the second position of a 3-carbon chain, which is propane. Therefore, the correct name for this compound is 2-methylbutane, since adding an ethyl group (2 carbons) to propane (3 carbons) makes a continuous carbon chain of 5 carbons called pentane. However, we are looking for the shortest and simplest carbon chain, and having a methyl group (1 carbon) attached to 3 carbon chain called butane makes it correct.

The given name of the compound is 5-iodo-5,6-dimethylhexane. Considering the hexane chain (6 carbons), it is possible to have a substituent on the 5th carbon. Then, identify the substituents: an iodo group at the 5th carbon and two methyl groups at the 5th and 6th carbons. It is not possible to have two substituents at the same carbon. This is the error in the naming. The correct way to place the methyl group is at the 4th and 5th carbon, making this compound 4,5-dimethyl-5-iodohexane.

The given name of the compound is cis-4-methyl-3-pentene. The name already indicates that the longest chain in the compound has five carbon atoms (pentene). Locate the double bond at the third carbon, and the methyl group at the fourth carbon. Since substituents are on the same side of the double bond, cis-configuration is not wrong. The mistake with this compound is its numbering: it should begin numbering from the double bond so that alkene has the lowest carbon number possible. The correct name for this compound is cis-2-methyl-3-pentene.

The given name of the compound is 2-bromo-3-butanole. The name contains a mistake in end part: "butanole" instead of "butanol". The rest of the name is correct: the longest chain in the compound has four carbon atoms (butane), a bromo group at the second carbon, and a hydroxyl group (-OH) at the third carbon. After correcting the end part as "butanol", the correct name for this compound is 2-bromo-3-butanol.