Nomenclature Of Organic Compounds(11th And 12th > Chemistry ) Questions and Answers
Explanation:-
Answer: Option C. -> 2,2-Dimethylpropane:
C
C5H12 is of the form CnH2n+2.
Hence it is a saturated alkane. Further, it is given that it has a quaternary carbon. Hence its structure is:
Longest chain = 3 carbons ⇒ word root = prop
                           Primary suffix = ane
                         Secondary prefix = 2,2-Dimethyl
IUPAC name is (c) 2,2-Dimethyl propane   Â
Explanation:-
Answer: Option C. -> 1-Ethyl-2-Methylcyclohexane:
C
The numbering is according to the lowest of locants, which gives us two options.
In this case, numbering happens according to alphabetical order. So ethyl group will have the lower number.
word root = hex
primary prefix = cyclo
secondary prefix = 1-Ethyl-2-methyl
primary suffix = ane
IUPAC name is
(c)1-Ethyl-2-methylcyclohexane
Explanation:-
Answer: Option B. -> 5, 5-Bis(1,1-dimethylpropyl)-2-methyldecane:
B
Decide the parent chain and give the numbering so that more substituted substituent will get the least number.
parent chain
10 carbons ⇒ word root ⇒ dec
single bond ⇒ suffix ⇒ ane
substituents at C5 and C2
There is one more same substituent on C5
Therefore,
  5,5-Bis-(1,1-dimethyl propyl)
Bis⇒ Because two same substituents are there, and a methyl group at C2⇒ 2-methyl
Therefore,
  5,5-Bis-(1,1-dimethylpropyl)-2-methyldecane
Explanation:-
Answer: Option B. -> 3-Ethyl-2,3-dimethylpentane:
B
Decide parent chain.
Numbering so that more substituted substituent will get the lowest number.
Five carbons ⇒ word root = pent
                  single bonds = ane(suffix)
→ substituent at C2 and C3
⇒ 3-ethyl-2, 3-dimethylpentane(alphabetically)
Therefore,
               (b) 3-Ethyl-2,3-dimethylpentane
Explanation:-
Answer: Option A. -> 2,4-Dimethylheptane:
A
Our first step should be to choose the longest chain from the given alkane.
Although there are 9 carbon atoms in total, the longest chain contains only 7 carbon atoms.
Word root = heptÂ
If we number the chain, as shown above, the two methyl substituents are at C4 and C6
Now, let's look at another case.
Now we have substituents at C2 and C4. In both cases, there are exactly two substituents.
We choose the numbering direction that gives the lowest set of locants.
Hence, secondary prefix = 2,4-dimethyl (since there are two methyl groups-one each at C2 and C4
Hence, the IUPAC name is 2,4-Dimethylheptane
Â
Explanation:-
Answer: Option A. -> 3-Ethyl-4,4-dimethylheptane:
A
First, check the parent chain.
Now, give numbers such that the more substituted substituent will get the lowest number.
Parent chain
7 carbon ⇒ hept (word root)
Single bonds ⇒ ane (suffix
→ substituent at C3 and C4 3-ethyl-4,4-dimethyl(alphabetically)
Therefore, 3-Ethyl-4,4-dimethylheptane
Explanation:-
Answer: Option D. -> 2-Chloro-2-methylpropane:
D
The given compound tertiary butyl chloride is
The longest chain clearly includes 3 carbon atoms
⇒  root word = prop
primary suffix = ane
Secondary prefix = 2-chloro-2-methyl
Hence the name (systematic IUPAC) of given compound is:
(d)Â 2-Chloro-2-methylpropane
Explanation:-
Answer: Option A. -> 3,6-Dimethyl-3-octene:
A
Parent chain is
1CH3−2CH2−3C|CH3=4CH−5CH2−CH36|CH−7CH2−8CH3
Word root ⇒ oct
Double bond ⇒ suffix ⇒ ene
Two methyl groups at C3 and C5 ⇒ 3,6-dimethyl
Therefore, 3,6-Dimethyl-3-octene