Be sure to answer all parts. The following IUPAC name is incorrect. Which of the following is the best explanation for why the name is incorrect? 3−butyl−2,2−dimethylhexane The longest chain was not chosen. The compound is spelled incorrectly. The compound is alphabetized incorrectly. The compound has incorrectly labeled substituents. Correct the name: 1−ethyl−1−tert−butylpentane 4−tert−butyloctane (1,1,1−trimethyl)−sec−butylpentane tert−butyloctane

Which of the following is the best explanation for why the name is incorrect?

- The longest chain was not chosen.

- 4−tert−butyloctane

Explanation:

Let's think in the condensed formula:

CH₃C(CH₃)₂CH((CH₂)₃CH₃)CH₂CH₂CH₃.

We see that in the second carbon, we have two methyls and in the third carbon a butyl group.

But the name is incorrect because the longest chain was not chosen.

For IUPAC rules we have to determine:

- The longest main chain.

- From two chains of equal length, we may choose the most branched chain.

- It must be numbered starting from the end that has the closest branch.

- Each remainder is named as a substitute for the main chain

If we draw the alkane we have:

        CH₃

           |  

CH₃ - C  - - CH - - CH₂ -- CH₂ -- CH₃

          |         |

        CH₃   CH₂

                    |

                  CH₂

                    |

                  CH₂

                    |

                  CH₃

The carbon in black, is the first carbon, if we start to number from the underlined carbon, we would have the first branch at carbon 5. We have 8 carbons, so if we start to count from the black carbon (carbon 1), the branch will be at the carbon 4, that's the main chain.

So finally, at the carbon 4 we have a tertiary carbon (it is a single carbon which is joined with 3 others carbons, and the single carbon is it joined to the main chain). That is the tert-butyl group.

As it is in the fourth position, we can say that the alkane's name is 4−tert−butyloctane.

Notice that tert-butyl is a common name but it is available by IUPAC.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

it should be p1 v1 = p2 v2