1. Identifying alkanes
Answer:
d. C₁₄H₃₀
Explanation:
The general formula of an alkane is [tex]\text{C}_{n}\text{H}_{2n+2}[/tex], where n is the number of C atoms.
If n = 14, 2n+2 =30. This compound is an alkane
a. is wrong. 2n+2 = 6. There is a deficiency of four H atoms.
b. is wrong. 2n+2 = 12. There is a deficiency of two H atoms.
c. is wrong. 2n+2 = 16. There is a deficiency of four H atoms.
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2. Identifying isomers
Answer:
a. C₃H₈
Explanation:
A 3-carbon alkane is too short to have isomers. The smallest alkane that can have isomers has four carbon atoms.
Thus a. (9 isomers), b. (3 isomers) and d. (many isomers!) are all wrong.
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3. Naming alkanes
Answer:
a. 2,2-Dimethylbutane.
Explanation:
1. Identify and name the longest continuous chain of carbon atoms (the main chain has 4 C; ∴ base name = butane).
2. Identify and name all the substituents [two 1C substituents (methyl)].
3. Number the main chain from the end closest to a substituent.
4. Identify the substituents by the number of the C atom on the main chain. Use hyphens between letters and numbers (2-methyl).
5. When there is more than one substituent of the same type, identify each substituent by its locating number and use a multiplying prefix to show the number of each substituent. Use commas between numbers (2,2-dimethyl).
6. Put the names of the substituents in front of the base name with no spaces. The name is 2,2-dimethylbutane.
