Nomenclature of organic compounds Questions in English

(D) The carbonyl group (ketone) has higher priority than the double bond and the bromine substituent. Therefore,the numbering must start from the end closest to the carbonyl group.
The structure is $Br(7)CH_2-CH_2(6)-CH(5)=CH(4)-CH_2(3)-CO(2)-CH_3(1)$.
The parent chain has $7$ carbons,so the root is 'hept'.
There is a double bond at position $4$ and a ketone at position $2$.
The bromine substituent is at position $7$.
Combining these,the $IUPAC$ name is $7-$bromohept$-4-$en$-2-$one.
Thus,the correct option is $D$.

(D) $1$. In cyclic compounds containing a double bond,the double bond is given priority in numbering.
$2$. The carbon atoms of the double bond are assigned positions $1$ and $2$ such that the substituent gets the lowest possible locant.
$3$. Starting from the double bond,if we number in the direction that gives the methoxy group position $4$,we get $4-$methoxycyclohexene.
$4$. Therefore,the correct $IUPAC$ name is $4-$methoxycyclohexene.

(C) $1$. Identify the principal functional group. The nitrile group $(-CN)$ has higher priority than the ketone group $(>C=O)$.
$2$. Number the carbon chain starting from the carbon of the nitrile group as $C-1$.
$3$. The chain is $CH_3-C(=O)-CH_2-CH_2-CN$. Counting from the nitrile carbon: $C-1$ is the nitrile carbon,$C-2$ is $CH_2$,$C-3$ is $CH_2$,$C-4$ is the carbonyl carbon,and $C-5$ is the terminal methyl group.
$4$. The parent chain has $5$ carbons,so it is a pentanenitrile derivative.
$5$. The ketone group is at position $4$,so it is named as an oxo substituent.
$6$. The correct $IUPAC$ name is $4-$oxopentanenitrile.

(C) According to the $IUPAC$ priority rules for functional groups,the order of priority is as follows:
$1. -COOR$ (Ester)
$2. -CN$ (Nitrile/Cyano)
$3. >C=O$ (Ketone)
$4. -NH_2$ (Amine)
Comparing this with the given groups:
$(iv) -COOR$
$(iii) -CN$
$(i) >C=O$
$(ii) -NH_2$
Thus,the correct order of priority is $(iv) > (iii) > (i) > (ii)$.

(A) $1$. Identify the longest carbon chain containing the double bonds. The structure is $(CH_3)_2CH-CH=CH-CH=CH-CH(C_2H_5)-CH_3$.
$2$. The longest chain has $9$ carbon atoms,so the parent alkane is nonane.
$3$. Numbering the chain from the left gives the double bonds at positions $3$ and $5$.
$4$. There are methyl groups at positions $2$ and $7$.
$5$. The $IUPAC$ name is $2, 7$-dimethyl-$3, 5$-nonadiene.

(D) The given compound is an ether with the structure $C_2H_5-O-CH(CH_3)_2$.
According to $IUPAC$ nomenclature rules for ethers,they are named as alkoxyalkanes.
The larger alkyl group is taken as the parent alkane,and the smaller alkyl group along with the oxygen atom is named as the alkoxy group.
Here,the ethoxy group $(-OC_2H_5)$ is attached to the second carbon of the propane chain.
Therefore,the correct $IUPAC$ name is $2-$ethoxypropane.

(A) $1$. Identify the longest carbon chain containing the principal functional group $(-OH)$ and the double bond $(C=C)$. The chain has $6$ carbon atoms,so the parent alkane is hexane.
$2$. Number the chain starting from the end that gives the lowest locant to the principal functional group $(-OH)$. Numbering from right to left gives the $-OH$ group at position $2$.
$3$. The double bond is at position $3$,and the methyl substituent is at position $5$.
$4$. Combining these,the $IUPAC$ name is $5-$methylhex$-3-$en$-2-$ol.

(B) To determine the structure of $4-$bromo$-3-$methylbut$-1-$ene:
$1$. The parent chain is 'but$-1-$ene',which means a four-carbon chain with a double bond at the first position: $CH_2=CH-CH_2-CH_3$.
$2$. At the $3^{rd}$ carbon,there is a methyl group $(-CH_3)$: $CH_2=CH-CH(CH_3)-CH_3$.
$3$. At the $4^{th}$ carbon,there is a bromo group $(-Br)$: $CH_2=CH-CH(CH_3)-CH_2Br$.
Comparing this with the given options,option $B$ matches this structure.

(A) $1$. Identify the principal functional group: The carboxylic acid group $(-COOH)$ has the highest priority,so the parent chain is a heptanoic acid derivative,and the carbon of $-COOH$ is $C-1$.
$2$. Number the chain: Starting from the carboxylic acid carbon as $C-1$,the chain is numbered as follows: $C-1$ $(-COOH)$,$C-2$ $(-CHBr)$,$C-3$ $(-CH_2)$,$C-4$ $(-CH_2)$,$C-5$ $(C=O)$,$C-6$ $(-CH_2)$,$C-7$ $(-CH_2OH)$.
$3$. Identify substituents and their positions: There is a bromo group at $C-2$,an oxo group at $C-5$,and a hydroxy group at $C-7$.
$4$. Assemble the name: Alphabetical order for substituents is Bromo,Hydroxy,Oxo. Thus,the name is $2-$Bromo$-7-$hydroxy$-5-$oxoheptanoic acid.

(A) $1$. Identify the longest carbon chain containing the principal functional group $(-OH)$,the double bond,and the triple bond. The chain has $7$ carbons,so the parent alkane is heptane.
$2$. Number the chain to give the lowest possible locants to the functional groups. The $-OH$ group gets priority,so we number from the right side: $C1$ is the alkyne carbon,$C4$ is the carbon with $-OH$,$C6$ is the carbon with the double bond,and $C2$ is the carbon with the ethyl group.
$3$. The structure is $2-$ethyl$-5-$methylhept$-6-$en$-1-$yn$-4-$ol.
$4$. Comparing with the options,the correct $IUPAC$ name is $2-$ethyl$-5-$methylhept$-6-$en$-1-$yn$-4-$ol.

(C) $1$. Identify the principal functional group: The nitrile group $(-CN)$ has the highest priority,so the parent chain is a nitrile (hexanenitrile).
$2$. Number the chain: The carbon of the $-CN$ group is $C-1$.
$3$. Identify substituents and their positions:
- $C-1$: Nitrile carbon
- $C-2$: Bromo group $(-Br)$
- $C-3$: Ketone group $(=O)$
- $C-5$: Hydroxy group $(-OH)$
- $C-6$: Amino group $(-NH_2)$
$4$. Assemble the name: Alphabetical order for substituents is Amino,Bromo,Hydroxy,Oxo.
- $6-$Amino
- $2-$Bromo
- $5-$hydroxy
- $3-$oxo
- Parent chain: hexanenitrile
Combining these,the $IUPAC$ name is $6-$Amino$-2-$bromo$-5-$hydroxy$-3-$oxohexanenitrile.

(B) $1$. Identify the longest carbon chain containing the principal functional group $(-OH)$ and the double bond. The chain has $10$ carbons,so the parent alkane is decane.
$2$. Number the chain to give the lowest possible locants to the functional group $(-OH)$,then the double bond,and finally the substituents.
$3$. Starting from the right,the $-OH$ group is at $C-4$,the double bond starts at $C-6$,and the ethyl group is at $C-5$. However,the standard $IUPAC$ numbering gives the $-OH$ group the lowest locant $4$.
$4$. Following the numbering shown in the provided solution image: the $-OH$ group is at $C-7$,the double bond is at $C-4$,and the methyl group is at $C-2$.
$5$. The correct $IUPAC$ name is $2-$methyl$-6-$ethyldec$-4-$en$-7-$ol.

(A) $1$. Identify the principal functional group: The molecule contains an amino group $(-NH_2)$,a ketone group $(>C=O)$,and a hydroxyl group $(-OH)$. According to $IUPAC$ priority rules,the ketone group has higher priority than the alcohol and amine groups. Therefore,the suffix will be '-one'.
$2$. Select the longest carbon chain containing the principal functional group: The longest chain containing the ketone group has $6$ carbons.
$3$. Number the chain: Numbering should start from the end that gives the ketone group the lowest possible locant. Numbering from right to left,the ketone is at position $2$. The chain is numbered as follows: $C_1(H_2OH)-C_2(=O)-C_3(CH_3)=C_4(H)-C_5(H, NH_2)-C_6(H_3)$.
$4$. Identify substituents and their positions: There is an amino group at position $5$,a methyl group at position $3$,and a hydroxy group at position $1$.
$5$. Assemble the name: Combining these,we get $5-$amino$-1-$hydroxy$-3-$methylhex$-3-$en$-2-$one.

(B) Let us analyze each option:
$A$: The structure shows a phenol ring with methyl groups at positions $3$ and $4$. This is $3, 4-$dimethylphenol. This is correct.
$B$: The structure shows a benzene ring with a chlorine atom at position $1$ and nitro groups at positions $2$ and $4$. The $IUPAC$ name should be $1-$chloro$-2, 4-$dinitrobenzene. The given name $4-$chloro$-1, 3-$dinitrobenzene is incorrect.
$C$: The structure shows a benzene ring with a methyl group at position $1$,a chlorine atom at position $2$,and a nitro group at position $4$. This is $2-$chloro$-1-$methyl$-4-$nitrobenzene. This is correct.
$D$: The structure shows an aniline ring with a methyl group at position $2$ and an ethyl group at position $4$. This is $4-$ethyl$-2-$methylaniline. This is correct.
Therefore,the option that is not correctly matched is $B$.

(B) The given compound is a benzene derivative with three substituents: $-C_2H_5$ (ethyl),$-Br$ (bromo),and $-NO_2$ (nitro).
According to $IUPAC$ rules for substituted benzenes,the substituents are listed in alphabetical order: Bromo,Ethyl,Nitro.
The numbering is assigned to give the lowest possible locants to the substituents.
Starting from the ethyl group as position $1$ (since it is the parent substituent in this specific arrangement context or to minimize locants),the bromo group is at position $2$ and the nitro group is at position $4$.
Thus,the name is $2-$Bromo$-1-$ethyl$-4-$nitrobenzene.

(D) $1$. Identify the longest carbon chain containing the principal functional group (hydroxy group) and the double bond. The chain has $9$ carbon atoms (nonene derivative).
$2$. Number the chain from the end that gives the lowest locant to the principal functional group ($-OH$ at $C-3$).
$3$. Substituents are: $5-$chloro,$4-$fluoro,and $4,5-$dimethyl.
$4$. The double bond starts at $C-7$.
$5$. Combining these,the $IUPAC$ name is $5-$chloro$-4-$fluoro$-4,5-$dimethylnon$-7-$en$-3-$ol.

(D) $1$. Identify the principal functional group: The hydroxyl group $(-OH)$ has higher priority than the amine group $(-NH_2)$ and the double bond. Thus,the suffix is $-ol$ and the numbering starts from the end closer to the $-OH$ group.
$2$. Determine the longest carbon chain: The longest chain containing the $-OH$ group,the double bond,and the $-NH_2$ group has $9$ carbon atoms (nonene).
$3$. Numbering the chain: Numbering from the right side gives the $-OH$ group at $C-3$,the double bond starts at $C-4$,the $-NH_2$ group is at $C-6$,and the $2,2-$dimethylpropyl group is at $C-5$.
$4$. Assemble the name: $6-$Amino$-5-(2,2-$dimethylpropyl$)$ non$-4-$en$-3-$ol.

(C) $1$. Identify the longest carbon chain. The longest chain contains $6$ carbon atoms,so the parent alkane is hexane.
$2$. Number the chain from the end that gives the substituents the lowest possible locants. Numbering from right to left gives substituents at positions $3$ and $4$.
$3$. The substituents are an ethyl group at position $3$ and a methyl group at position $4$.
$4$. Combining these,the $IUPAC$ name is $3-\text{Ethyl}-4-\text{methylhexane}$.

(D) $1$. Identify the principal functional group: The aldehyde group $(-CHO)$ has the highest priority,so the parent chain must include it and start numbering from the carbonyl carbon as $C-1$.
$2$. Select the longest carbon chain containing the principal functional group and the double bond: The longest chain containing the $-CHO$ group and the $C=C$ bond has $7$ carbon atoms (heptenal).
$3$. Numbering the chain: Starting from the aldehyde carbon $(C-1)$,the double bond starts at $C-3$,the methyl group is at $C-3$,the hydroxyl group is at $C-5$,and the ethyl group is at $C-2$.
$4$. Assemble the name: Alphabetical order for substituents is ethyl,hydroxy,methyl. Thus,the name is $2-$ethyl$-5-$hydroxy$-3-$methylhept$-3-$enal.

(A) $1$. Identify the principal functional group: The $-OH$ group is the principal functional group,so the carbon attached to it is assigned position $1$.
$2$. Number the ring: Number the ring to give the lowest possible locants to the double bond and substituents. Starting from the carbon with $-OH$ as $1$,we move towards the double bond to give it the lowest number. Thus,the double bond starts at position $2$.
$3$. Locate substituents: The two methyl groups are at position $5$.
$4$. Combine the parts: The parent chain is a cyclohexene ring. With the $-OH$ at $1$,the double bond at $2$,and two methyl groups at $5$,the $IUPAC$ name is $5, 5-$dimethylcyclohex$-2-$en$-1-$ol.

(C) $1$. Identify the longest carbon chain containing the principal functional group (aldehyde). The chain has $5$ carbons,so the parent alkane is pentane,and the suffix is $-al$ (pentanal).
$2$. Number the chain starting from the aldehyde carbon as $C-1$.
$3$. The substituent at $C-2$ is an ethyl group $(-CH_2CH_3)$ and the substituent at $C-4$ is a chloro group $(-Cl)$.
$4$. Arrange the substituents alphabetically: $4-$chloro and $2-$ethyl.
$5$. Combining these,the $IUPAC$ name is $4-$chloro$-2-$ethylpentanal.

(C) The given compound is a substituted cyclohexanone.
$1$. The principal functional group is the ketone $(-C=O)$,so the carbon attached to the oxygen is numbered $1$.
$2$. We number the ring to give the substituents the lowest possible locants.
$3$. Starting from the ketone carbon as $1$,moving towards the ethyl group gives the ethyl group at position $3$ and the hydroxyl group at position $4$.
$4$. Thus,the $IUPAC$ name is $3-$ethyl$-4-$hydroxycyclohexanone.

(C) The structure of isoprene is $CH_2=C(CH_3)-CH=CH_2$.
To name it according to $IUPAC$ rules:
$1$. Select the longest carbon chain containing the double bonds,which is a $4-$carbon chain (buta-).
$2$. Number the chain from the end that gives the lowest locants to the double bonds: $1, 2, 3, 4$.
$3$. There is a methyl group at position $2$.
$4$. The double bonds are at positions $1$ and $3$.
Therefore,the $IUPAC$ name is $2-$methyl$-1,3-$butadiene.

(D) The given compound is an ether with the structure $C_2H_5-O-CH(CH_3)_2$.
According to $IUPAC$ nomenclature for ethers,they are named as alkoxyalkanes.
The larger alkyl group is considered the parent alkane,and the smaller alkyl group along with the oxygen atom is named as an alkoxy group.
Here,the ethyl group $(C_2H_5-)$ is smaller than the isopropyl group $(-CH(CH_3)_2)$,so it is named as an ethoxy group.
The parent chain is propane,and the ethoxy group is attached to the second carbon atom.
Therefore,the $IUPAC$ name is $2-\text{ethoxypropane}$.

(A) According to the Cahn-Ingold-Prelog $(CIP)$ sequence rules,priority is assigned based on the atomic number of the atom directly attached to the chiral center.
$1$. The atom with the higher atomic number gets higher priority.
$2$. Comparing the atoms attached to the chiral center: $O$ (atomic number $8$) in $-OH$ has the highest priority.
$3$. For the remaining groups ($-COOH$,$-CHO$,$-CH_2OH$),the atom attached is $C$ (atomic number $6$).
$4$. We look at the next atoms:
- In $-COOH$ ($C$ is bonded to $O, O, O$ via double bond equivalent),
- In $-CHO$ ($C$ is bonded to $O, O, H$ via double bond equivalent),
- In $-CH_2OH$ ($C$ is bonded to $O, H, H$).
Comparing these,the order is $-COOH > -CHO > -CH_2OH$.
Thus,the overall priority order is $-OH > -COOH > -CHO > -CH_2OH$.

(A) $1$. Identify the longest carbon chain containing the principal functional group $(-OH)$ and the double bond $(C=C)$. The chain has $6$ carbon atoms,so the parent alkane is hexane.
$2$. Number the chain from the end that gives the lowest possible locant to the principal functional group $(-OH)$. Numbering from right to left,the $-OH$ group is at position $2$.
$3$. The double bond starts at carbon $3$,so it is a hex-$3$-ene derivative.
$4$. There is a methyl group $(-CH_3)$ at position $5$.
$5$. Combining these,the $IUPAC$ name is $5$-methylhex-$3$-en-$2$-ol.

(B) To determine the structure of $4$-bromo-$3$-methylbut-$1$-ene,we analyze the $IUPAC$ name:
$1$. The parent chain is 'but$-1-$ene',which means a four-carbon chain with a double bond at the first position: $CH_2=CH-CH_2-CH_3$.
$2$. The substituent '$3$-methyl' indicates a methyl group $(-CH_3)$ attached to the third carbon atom.
$3$. The substituent '$4$-bromo' indicates a bromine atom $(-Br)$ attached to the fourth carbon atom.
$4$. Combining these,the structure is $CH_2=CH-CH(CH_3)-CH_2Br$.
Thus,the correct option is $B$.

(D) The $IUPAC$ name $2$-methyl-$2$-butene indicates a $4$-carbon chain (butene) with a double bond at the $2$-nd position and a methyl group at the $2$-nd position.
The structure is $CH_3-CH=C(CH_3)-CH_3$.
Therefore,the correct option is $D$.

(A) The structural representations of $n$-butane are as follows:
$1$. Condensed formula: $CH_3CH_2CH_2CH_3$ (represented by $I$).
$2$. Bond-line formula: $A$ zigzag line representing the carbon chain (represented by $II$).
$3$. Complete structural formula: Shows all bonds between atoms (represented by $III$).
Therefore,the order is $I, II, III$.

(B) $1$. Identify the principal functional group: The aldehyde group $(-CHO)$ has the highest priority and must be assigned the lowest possible number,so it is at position $1$.
$2$. Select the longest carbon chain containing the principal functional group and the double bond: The chain starting from the aldehyde carbon $(C-1)$ through the double bond gives a $4-$carbon chain (but$-2-$enal).
$3$. Number the chain: The aldehyde carbon is $C-1$,the carbon with the double bond is $C-2$,the next is $C-3$,and the terminal methyl is $C-4$.
$4$. Identify substituents: There is an ethyl group $(-CH_2CH_3)$ attached to $C-2$.
$5$. Combine: The $IUPAC$ name is $2-$ethylbut$-2-$enal.

(A) The structure is $Ph-CH_{2}-CH_{2}-COOH$.
To name this compound according to $IUPAC$ rules,we identify the longest carbon chain containing the carboxylic acid group as the parent chain.
The carbon atom of the $-COOH$ group is assigned position $1$.
The chain consists of $3$ carbons,so the parent alkane is propane.
The carboxylic acid suffix is $-oic$ acid.
There is a phenyl group attached to the $3^{rd}$ carbon atom.
Therefore,the correct name is $3-$phenylpropanoic acid.

(A) To determine the $IUPAC$ name,first identify the longest carbon chain containing the double bond. The longest chain has $7$ carbon atoms,so the parent alkane is heptane. The double bond is given priority and numbered to get the lowest possible locant. Numbering from the right side gives the double bond position at $2$. The substituents are methyl groups at positions $2, 5,$ and $6$. Thus,the $IUPAC$ name is $2,5,6-$trimethylhept$-2-$ene.

(C) $1$. Identify the principal functional group. The nitrile group $(-CN)$ has higher priority than the ketone group $(=O)$. Thus,the parent chain is a nitrile.
$2$. Number the chain starting from the carbon of the $-CN$ group as $C-1$.
$3$. The chain is $CH_3-C(CH_3)_2-CH_2-C(=O)-CH_3$. Numbering gives: $C-1$ (nitrile carbon),$C-2$ (quaternary carbon with two methyl groups),$C-3$ (methylene group),$C-4$ (ketone carbonyl),$C-5$ (terminal methyl).
$4$. The substituents are two methyl groups at $C-2$ and an oxo group at $C-4$.
$5$. Combining these,the $IUPAC$ name is $2,2-$dimethyl$-4-$oxopentanenitrile.

(C) The structure of $s$-butyl phenylvinyl methane can be broken down into its components:
$1$. $A$ methane core $(CH_4)$ where hydrogens are replaced by substituents.
$2$. An $s$-butyl group: $-CH(CH_3)CH_2CH_3$.
$3$. $A$ phenyl group: $-C_6H_5$ (or $Ph$).
$4$. $A$ vinyl group: $-CH=CH_2$.
Combining these,the central carbon is attached to one $H$,one $s$-butyl group,one phenyl group,and one vinyl group.
Looking at the structures provided,the structure in option $C$ represents $3$-phenyl-$4$-methylhex-$1$-ene,which is equivalent to $s$-butyl phenylvinyl methane.
The central carbon (position $3$) is attached to a vinyl group $(-CH=CH_2)$,a phenyl group $(-Ph)$,and an $s$-butyl group $(-CH(CH_3)CH_2CH_3)$.

(A) $1$. Identify the functional group: The compound is an ester,so the suffix is -oate. The alkyl group attached to the oxygen atom is a propyl group.
$2$. Number the main chain: The carbon atom of the ester group is $C-1$. The longest chain containing the ester group has $7$ carbons,making it a heptanoate derivative.
$3$. Identify substituents: There is a bromo group at position $2$ and a methyl group at position $5$.
$4$. Combine: The name is propyl $2$-bromo-$5$-methylheptanoate.

(C) The molar mass of $72 \text{ g mol}^{-1}$ corresponds to the molecular formula $C_5H_{12}$ (pentane isomers).
Let us analyze the number of primary carbon atoms in the isomers of $C_5H_{12}$:
$1$. $n$-pentane $(CH_3-CH_2-CH_2-CH_2-CH_3)$: It has two primary carbon atoms.
$2$. $2$-Methylbutane $(CH_3-CH(CH_3)-CH_2-CH_3)$: It has three primary carbon atoms.
$3$. $2,2$-Dimethylpropane $(C(CH_3)_4)$: It has four primary carbon atoms.
Therefore,the hydrocarbon $(x)$ with three primary carbon atoms is $2$-Methylbutane.

(C) The priority order of functional groups in $IUPAC$ nomenclature is determined by established rules. The general order is: $-CONH_2$ (Amide) $>$ $-COOR$ (Ester) $>$ $-CHO$ (Aldehyde) $>$ $>C=O$ (Ketone) $>$ $-CN$ (Nitrile) $>$ $-OH$ (Alcohol) $>$ $-NH_2$ (Amine) $>$ $-C=C-$ (Alkene) $>$ $-C \equiv C-$ (Alkyne).
Comparing the provided options:
Option $C$ lists: $-CONH_2$ (Amide) $>$ $-CHO$ (Aldehyde) $>$ $>C=O$ (Ketone) $>$ $-NH_2$ (Amine) $>$ $-C \equiv C-$ (Alkyne).
This sequence correctly follows the decreasing order of priority for the given groups.

(A) $1$. Identify the longest carbon chain: The longest continuous chain contains $7$ carbon atoms,so the parent alkane is heptane.
$2$. Numbering the chain: Number the chain from the end that gives the substituents the lowest possible locants. Numbering from left to right gives substituents at positions $3$ and $5$. Numbering from right to left also gives substituents at positions $3$ and $5$.
$3$. Alphabetical order: When locants are the same from both ends,the substituent that comes first alphabetically gets the lower number. Ethyl $(E)$ comes before methyl $(M)$. Therefore,the ethyl group is assigned position $3$ and the methyl group is assigned position $5$.
$4$. Final Name: $3$-ethyl-$5$-methylheptane.