Answer:
Choice a. The compound name is alphabetized incorrectly.
The correct IUPAC name of this compound should be:
4-ethyl-2,2-dimethylheptane.
Explanation:
Draw the carbon backbone structure for "2,2-dimethyl-4-ethylheptane":
.
The seven-carbon backbone is indeed the longest chain in this compound.
.
Numbering from the end with the two methyl groups indeed minimizes the number on each group. However, the alphabetical order of the groups is not correct. There are two kinds of substitute groups in this compound:
- Two methyl groups, and
- One ethyl group.
The name for them will be
- 2,2-dimethyl, and
- 4-ethyl.
Ignore the multiplier prefixes (di-, tri-, etc.) while alphabetizing.
The ethyl group shall be placed before the two methyl groups. The name of the compound shall be:
4-ethyl-2,2-dimethylheptane.
Answer: Option (d) is the correct answer.
Explanation:
It is given that molecular formula is . Now, we will calculate the degree of unsaturation as follows.
Degree of unsaturation =
=
= 9 - 8 + 1
= 2
As the degree of unsaturation comes out to be 2. It means that this compound will contain one ring and one double bond.
Yes, this compound could be an alkyne as for alkyne D.B.E = 2.
But this compound cannot be a cycloalkane because for a cycloalkane D.B.E = 1 which is due to the ring only.
Thus, we can conclude that it is a cycloalkane is not a structural possibility for this hydrocarbon.