Nomenclature of organic compounds Questions in English

(B) The common name 'Sugar of lead' refers to lead$(II)$ acetate.
Its chemical formula is $(CH_3COO)_2Pb$.
Therefore,the correct option is $(B)$.

(B) The principal functional group is the hydroxyl group $(-OH)$,which is assigned the lowest possible locant.
Numbering the carbon chain from right to left gives the hydroxyl group the position $1$.
The structure is $C^3H_3-C^2H(Br)-C^1H_2OH$.
The bromine atom is attached to the $C^2$ atom.
Therefore,the systematic $IUPAC$ name is $2$-bromopropan-$1$-ol.

(B) Acetylsalicylic acid,commonly known as aspirin,has a benzene ring with a carboxylic acid group $(-COOH)$ at the $C-1$ position and an acetoxy group $(-OCOCH_3)$ at the $C-2$ position.
Therefore,its $IUPAC$ name is $2-$acetoxybenzoic acid.

(D) The functional group present is an aldehyde group,$-CHO$.
The compound $CH_3CHO$ contains two carbon atoms in its longest chain.
For a two-carbon aldehyde,the parent alkane is ethane,and the suffix for an aldehyde is $-al$.
Therefore,the $IUPAC$ name is $Ethanal$.

(A) The carboxylic acid functional group $(-COOH)$ has higher priority than the hydroxyl group $(-OH)$.
Numbering of the carbon chain starts from the carbon of the carboxylic acid group,assigning it as $C-1$.
The chain consists of $5$ carbon atoms,making it a pentanoic acid derivative.
The $-OH$ group is attached to the $4^{th}$ carbon atom.
Therefore,the $IUPAC$ name is $4-$hydroxypentanoic acid.

(B) In $IUPAC$ nomenclature for ethers,the oxygen atom is associated with the smaller alkyl group to form an alkoxy substituent,while the larger alkyl group is treated as the parent alkane.
Here,the structure is $CH_3-O-C_2H_5$.
The smaller group is $CH_3$ (methyl),which forms the methoxy group $(-OCH_3)$.
The larger group is $C_2H_5$ (ethyl),which acts as the parent alkane (ethane).
Therefore,the $IUPAC$ name is $Methoxyethane$.

(A) The given structure is $CH_3-CH(CH_3)-CH(CH_3)-CH_3$.
First,identify the longest carbon chain,which contains $4$ carbon atoms (butane).
Number the chain from either end to give the lowest possible locants to the substituents.
Methyl groups are present at the $2nd$ and $3rd$ carbon atoms.
Therefore,the $IUPAC$ name is $2, 3-$dimethylbutane.

(B) The longest carbon chain contains $6$ carbon atoms.
We number the chain from the right side to give the hydroxyl $(-OH)$ group the lowest possible locant,which is $2$.
The substituent is a methyl group $(-CH_3)$ located at the $C-4$ position.
Therefore,the $IUPAC$ name is $4-$methyl$-2-$hexanol.

(D) $1$. Identify the longest carbon chain containing the double bond. The longest chain has $5$ carbon atoms,so the parent alkane is pentene.
$2$. Number the chain from the end that gives the double bond the lowest possible locant. Numbering from left to right gives the double bond at position $2$.
$3$. Identify the substituent. There is a methyl group at position $3$.
$4$. Combining these,the name is $3-$methylpent$-2-$ene or $3-$methyl$-2-$pentene.

(B) The given compound is $CH_3C \equiv N$.
In $IUPAC$ nomenclature,nitriles are named by adding the suffix 'nitrile' to the name of the corresponding alkane (including the carbon atom of the cyano group).
The chain contains two carbon atoms ($CH_3$ and $CN$),so the parent alkane is ethane.
Therefore,the $IUPAC$ name is ethanenitrile.

(C) The $IUPAC$ name $2, 2, 3-$trimethylhexane indicates a hexane parent chain (six carbon atoms).
At position $2$,there are two methyl groups,and at position $3$,there is one methyl group.
The structure is $CH_3-C(CH_3)_2-CH(CH_3)-CH_2-CH_2-CH_3$ is not correct as per the name.
Let us re-evaluate: $2, 2, 3-$trimethylhexane corresponds to the structure $CH_3-C(CH_3)_2-CH(CH_3)-CH_2-CH_2-CH_3$ is actually $2, 2, 3-$trimethylhexane.
Wait,let us count the carbons: $CH_3(1)-C(2)(CH_3)_2-CH(3)(CH_3)-CH_2(4)-CH_2(5)-CH_3(6)$. This is $2, 2, 3-$trimethylhexane.
Option $A$ is $2, 2, 3-$trimethylpentane.
Option $B$ is $2, 2, 4-$trimethylpentane.
Option $C$ is $2, 2, 3-$trimethylhexane.

(A) The given compound is $CH_3CH_2COCH_2CH_3$.
It contains a ketone functional group $(>C=O)$.
The longest carbon chain contains $5$ carbon atoms,so the parent alkane is pentane.
Numbering the chain from either side gives the ketone group at position $3$.
Therefore,the $IUPAC$ name is pentan$-3-$one or $3-$pentanone.

(B) The given compound $CH_3COOC_2H_5$ is an ester with the general formula $R-COO-R'$.
In $IUPAC$ nomenclature,esters are named as alkyl alkanoates.
The alkyl group attached to the oxygen atom is named first,which is ethyl ($C_2H_5$ in this case).
The remaining part containing the carbonyl group is named as an alkanoate based on the total number of carbon atoms in the acid part (including the carbonyl carbon).
Here,$CH_3COO-$ corresponds to a two-carbon chain,which is ethanoate.
Therefore,the $IUPAC$ name is ethyl ethanoate.

(B) $1$. Identify the longest carbon chain containing the double bond. The chain has $5$ carbon atoms,so the parent alkane is pentane,and the alkene is pentene.
$2$. Number the chain from the end that gives the double bond the lowest possible locant. Numbering from the right gives the double bond the position $2$ ($CH_3-CH=CH-CH(CH_3)_2$ numbering $1,2,3,4,5$).
$3$. Identify the substituent: there is a methyl group at position $4$.
$4$. Combining these,the name is $4-$methylpent$-2-$ene.

(B) To name the compound $CH_2=CH-CH(CH_3)_2$ according to $IUPAC$ rules:
$1$. Identify the longest carbon chain containing the double bond. The longest chain has $4$ carbon atoms.
$2$. Number the chain starting from the end closer to the double bond. The double bond starts at carbon $1$.
$3$. The substituent (methyl group) is at position $3$.
$4$. Combining these,the name is $3-$methylbut$-1-$ene or $3-$methyl$-1-$butene.

(B) The longest carbon chain contains $6$ carbon atoms,which corresponds to the parent alkane $hexane$.
Numbering the chain from the end that gives the substituent the lowest possible number,the methyl group is located at carbon-$3$.
Therefore,the $IUPAC$ name is $3-$methylhexane.

(C) $1$. Identify the longest carbon chain. The longest chain contains $3$ carbon atoms,which corresponds to the parent alkane 'propane'.
$2$. Identify the substituent. There is a methyl group $(-CH_3)$ attached to the second carbon atom.
$3$. Number the chain such that the substituent gets the lowest possible number. Numbering from either end gives the methyl group at position $2$.
$4$. Combine the parts: $2-$methylpropane.

(C) The carbon chain is numbered starting from the carbon atom attached to the two chlorine atoms to give the lowest possible locants to the substituents.
Since the parent alkane contains two carbon atoms,it is named as ethane.
Therefore,the $IUPAC$ name of the compound $CH_3-CHCl_2$ is $1, 1-$dichloroethane.

(C) $1$. Identify the longest carbon chain. The longest chain contains $10$ carbon atoms,which is a decane chain.
$2$. Number the chain from the end that gives the substituents the lowest possible locants. Numbering from the right gives the substituents at positions $4$ and $5$.
$3$. At position $4$,there is an ethyl group $(-CH_2-CH_3)$ and a methyl group $(-CH_3)$. At position $5$,there is another methyl group $(-CH_3)$.
$4$. Combining these,the name is $4$-ethyl-$4,5$-dimethyldecane,which is alphabetically ordered as $4,5$-dimethyl-$4$-ethyldecane.

(B) The given compound is $CH_3-CH(CH_3)-CH_2-CH=CH_2$.
To name this compound according to $IUPAC$ rules,we first select the longest carbon chain containing the double bond.
The numbering starts from the end closer to the double bond,so the double bond is at position $1$.
The methyl group is attached to the carbon at position $4$.
Therefore,the $IUPAC$ name is $4-$methylpent$-1-$ene.

(A) To determine the $IUPAC$ name,follow these steps:
$1$. Identify the longest carbon chain containing the double bond. The longest chain has $4$ carbon atoms,so the parent alkane is butane.
$2$. Number the chain starting from the end that gives the double bond the lowest possible locant. Numbering from the right,the double bond starts at carbon $1$.
$3$. Identify substituents. There is a methyl group at position $2$.
$4$. Combining these,the name is $2-$methylbut$-1-$ene.

(A) The given structure is $CH_3-C \equiv C-CH(CH_3)_2$.
$1$. Identify the longest carbon chain containing the triple bond. The chain has $5$ carbon atoms,so the parent alkane is pentane,and the parent alkyne is $pent-2-yne$.
$2$. Number the chain from the end that gives the triple bond the lowest possible locant. Numbering from the left,the triple bond starts at carbon $2$.
$3$. Identify the substituent. There is a methyl group $(-CH_3)$ attached to the $4^{th}$ carbon.
$4$. Combining these,the $IUPAC$ name is $4-methylpent-2-yne$.

(B) The given structure is $C_2H_5-C(=CH_2)-CH(CH_3)-CH_3$.
To find the $IUPAC$ name,we first identify the longest carbon chain containing the double bond.
The longest chain has $5$ carbon atoms,so the parent alkane is pentene.
Numbering the chain from the end closer to the double bond gives the double bond at position $1$.
The structure is $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$.
Numbering from the right: $C_5H_3-C_4H_2-C_3(=CH_2)-C_2H(CH_3)-C_1H_3$ is incorrect.
Correct numbering: $CH_3(5)-CH_2(4)-C(3)(=CH_2(1))-CH(CH_3)(2)-CH_3(1)$ is not right.
Let's re-examine the longest chain: $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$.
The longest chain is $5$ carbons long: $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$.
Numbering to give the double bond the lowest locant: $CH_3(5)-CH_2(4)-C(3)(=CH_2(1))-CH(CH_3)(2)-CH_3(1)$ is wrong.
The longest chain is $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$ which is $2-$ethyl$-3-$methylbut$-1-$ene.
Wait,the longest chain is $5$ carbons: $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$.
Actually,the longest chain is $5$ carbons: $CH_3-CH_2-C(=CH_2)-CH(CH_3)-CH_3$.
The correct $IUPAC$ name is $2-$ethyl$-3-$methylbut$-1-$ene.

(A) The structure $(C_2H_5)_2CHCH_2OH$ can be expanded as $CH_3CH_2-CH(C_2H_5)-CH_2OH$.
To determine the $IUPAC$ name,we identify the longest carbon chain containing the principal functional group $(-OH)$.
The longest chain containing the $-OH$ group has $4$ carbon atoms (butane).
The carbon attached to the $-OH$ group is numbered as $1$.
At the $2^{nd}$ carbon position,there is an ethyl group $(-C_2H_5)$ attached.
Therefore,the $IUPAC$ name is $2-$ethylbutan$-1-$ol.

(B) In the compound $CH_3-CH(C_6H_5)-CH_2-CH_3$,the longest continuous carbon chain contains $4$ carbon atoms,which corresponds to the parent alkane butane.
The phenyl group $(C_6H_5)$ is attached as a substituent at the $2$nd carbon atom when numbered from the left to ensure the substituent receives the lowest possible locant.
Therefore,the $IUPAC$ name is $2$-phenylbutane.

(B) The longest carbon chain containing the carboxylic acid group has $3$ carbon atoms,which corresponds to the parent alkane $propane$.
Since there is a methyl group attached to the $2^{nd}$ carbon atom,the prefix is $2-$methyl.
Therefore,the $IUPAC$ name is $2-$methylpropanoic acid.

(B) The longest carbon chain containing the aldehyde group $(-CHO)$ has $4$ carbon atoms.
The numbering starts from the aldehyde carbon as $C-1$.
$A$ methyl group is present at the $C-2$ position.
Hence,the $IUPAC$ name is $2-methylbutanal$.

(D) The longest carbon chain containing the principal functional group $(-OH)$ has $4$ carbon atoms (butane).
Numbering starts from the right end to give the lowest possible locant $(1)$ to the $-OH$ group.
$A$ methyl substituent is present at the $3^{rd}$ carbon.
Hence,the correct $IUPAC$ name is $3-$methyl$-1-$butanol.

(B) $1$. Identify the principal functional group: The aldehyde group $(-CHO)$ has the highest priority,so the parent chain must include the carbon of the $-CHO$ group and it is assigned position $1$.
$2$. Select the longest carbon chain containing the principal functional group: The chain has $5$ carbons,so the parent alkane is pentane. The suffix for aldehyde is $-al$,so the parent name is pentanal.
$3$. Number the chain: The carbon of the $-CHO$ group is $C-1$. The methyl group $(-CH_3)$ is at $C-4$ and the hydroxyl group $(-OH)$ is at $C-4$.
$4$. Assemble the name: The substituents are $4-$hydroxy and $4-$methyl. Alphabetically,'h' comes before 'm'. Thus,the name is $4-$hydroxy$-4-$methylpentanal. However,re-evaluating the structure $CH_3-CH(OH)-CH_2-CH(CH_3)-CHO$: The chain is $C_1(CHO)-C_2(H)(CH_3)-C_3(H_2)-C_4(H)(OH)-C_5(H_3)$. The substituents are at position $4$ (hydroxy) and position $2$ (methyl). Therefore,the correct name is $4-$hydroxy$-2-$methylpentanal.

(D) Tertiary butyl alcohol has the structure $CH_3-C(CH_3)(OH)-CH_3$.
The longest carbon chain containing the $-OH$ group has $3$ carbon atoms $(propane)$.
$A$ methyl group and the hydroxyl group are both at the $2^{nd}$ carbon atom.
Therefore,the $IUPAC$ name is $2-methylpropan-2-ol$.

(A) $1$. Identify the principal functional group: The carboxylic acid group $(-COOH)$ has the highest priority,so the parent chain must include this carbon as $C-1$.
$2$. Number the chain: Starting from the $-COOH$ carbon,the chain is numbered as $C-1 (COOH), C-2 (CH_2), C-3 (CH), C-4 (CH), C-5 (CH(CH_3)), C-6 (CH_3)$.
$3$. Identify substituents and unsaturation: There is a methyl group at position $5$ and a double bond starting at position $3$.
$4$. Combine the parts: The parent alkane is hexane. With the double bond at $3$ and the acid group,it becomes hex$-3-$enoic acid. Adding the substituent,we get $5-$methylhex$-3-$enoic acid.

(C) The principal functional group is the alcohol $(-OH)$,so numbering starts from the carbon attached to the $-OH$ group.
$C^5H_3-C^4H_2-C^3H=C^2(CH_3)-C^1H_2OH$
The parent chain has $5$ carbon atoms (pent).
There is a double bond at $C-2$ ($-2$-en).
There is a methyl group at $C-2$ ($2$-methyl).
The alcohol group is at $C-1$ ($-1$-ol).
Therefore,the $IUPAC$ name is $2$-methylpent-$2$-en-$1$-ol.

(B) The $IUPAC$ name $4-$methylpent$-2-$ene indicates a pentene chain ($5$ carbons) with a double bond at the $C-2$ position and a methyl group at the $C-4$ position.
Option $A$: $(CH_3)_2CH-CH_2CH=CH_2$ is $4-$methylpent$-1-$ene.
Option $B$: $(CH_3)_2CH-CH=CH-CH_3$ is $4-$methylpent$-2-$ene.
Option $C$: $(CH_3)_2CH-CH_2CH=CH-CH_3$ is $5-$methylhex$-2-$ene.
Option $D$: $(CH_3)_2C=CHCH_2CH_3$ is $2-$methylpent$-2-$ene.
Therefore,the correct structure is $(CH_3)_2CH-CH=CH-CH_3$.

(A) Succinic acid has the chemical formula $HOOC-CH_2-CH_2-COOH$.
It contains a chain of $4$ carbon atoms with two carboxylic acid groups at the terminal positions.
According to $IUPAC$ nomenclature,the parent alkane is butane,and the suffix for two carboxylic acid groups is $dioic$ acid.
Therefore,the $IUPAC$ name is $butane-1, 4-dioic$ acid.

(C) To determine the $IUPAC$ name,we identify the longest carbon chain containing the functional group.
The structure is $CH_3-CH(CH_3)-CH_2-CH_2Br$.
The longest chain has $4$ carbon atoms (butane).
Numbering starts from the carbon attached to the bromine atom to give it the lowest possible locant.
At position $1$,there is a bromo group,and at position $3$,there is a methyl group.
Therefore,the $IUPAC$ name is $1-$bromo$-3-$methylbutane.

(C) The parent carbon chain is selected by including the principal functional group (carboxylic acid) and the double bond.
Numbering starts from the $COOH$ group as $C-1$.
The chain is $CH_3(7)-CH(6)=CH(5)-CH_2(4)-CH(NH_2)(3)-CH_2(2)-COOH(1)$.
There is an amino group at position $3$ and a double bond starting at position $5$.
Thus,the name is $3-$amino$-5-$heptenoic acid.

(D) The structure is $CH_2=CH-CH_2-Cl$.
According to $IUPAC$ rules,the double bond is given priority over the halogen substituent.
The chain is numbered starting from the end closer to the double bond.
Thus,the carbon attached to the double bond is $C-1$,the next is $C-2$,and the carbon attached to chlorine is $C-3$.
The name is $3-$chloro$-1-$propene.

(A) $CH_3CH_2COCl$ consists of three carbon atoms in the parent chain and an acyl chloride functional group $(-COCl)$.
The parent alkane with three carbon atoms is propane.
Replacing the suffix $-e$ with $-oyl \ chloride$ gives the name Propanoyl chloride.

(A) The given compound is $CH_2=CH-CH_2-CH_2OH$.
$1$. Identify the longest carbon chain containing the functional group $(-OH)$ and the double bond $(C=C)$. The chain has $4$ carbon atoms,so the parent alkane is butane.
$2$. Number the chain starting from the end closer to the functional group $(-OH)$. Thus,the $-OH$ group is at $C-1$ and the double bond starts at $C-3$.
$3$. The suffix for the alcohol is $-ol$ and for the alkene is $-ene$. Combining these,we get $but-3-en-1-ol$.

(B) The parent chain is a $6-$carbon chain (hex-).
The suffix $-1-$oic acid indicates a carboxylic acid group at position $1$.
The $-3-$yne indicates a triple bond starting at position $3$.
Numbering from the carboxylic acid carbon $(C1)$:
$C1$ $(COOH)$ $- C2 (CH_2) - C3 (C) \equiv C4 (C) - C5 (CH_2) - C6 (CH_3)$.
Thus,the structure is $CH_3-CH_2-C \equiv C-CH_2-COOH$.

(A) $1$. Identify the longest carbon chain containing both the double and triple bonds. The chain has $7$ carbons,so the parent alkane is heptane.
$2$. Number the chain from the end that gives the lowest locants to the multiple bonds. The triple bond at $C-1$ and the double bond at $C-5$ gives the set $(1, 5)$. Numbering from the other side would give $(2, 6)$. Thus,we number from the right.
$3$. Identify substituents: $6-$chloro,$4-$ethyl,and $5-$methyl.
$4$. Combine them alphabetically: $6-$chloro$-4-$ethyl$-5-$methylhept$-5-$en$-1-$yne.

(A) In the given compound $Cl_3C-CH_2-CHO$,the principal functional group is the aldehyde group $(-CHO)$.
The carbon atom of the $-CHO$ group is assigned the position $1$.
The chain is numbered as follows: $C_3(Cl_3)-C_2(H_2)-C_1(HO)$.
Since there are $3$ carbon atoms in the longest chain,the parent alkane is propane,and the suffix for the aldehyde is $-al$.
At position $3$,there are $3$ chlorine atoms,so the prefix is $3,3,3-$trichloro.
Combining these,the $IUPAC$ name is $3,3,3-$trichloropropanal.

(A) The given compound is $CH_3-CH(CH_3)-CH_2-CH_2-Cl$.
To determine the $IUPAC$ name,we identify the longest carbon chain,which contains $4$ carbon atoms (butane).
Numbering starts from the end closest to the substituent to give the lowest possible locants.
Starting from the carbon attached to the chlorine atom,we assign $C-1$ to the carbon with the $-Cl$ group,$C-2$ to the next,$C-3$ to the carbon with the $-CH_3$ group,and $C-4$ to the terminal carbon.
Thus,the substituent $-Cl$ is at position $1$ and the $-CH_3$ group is at position $3$.
Alphabetical order is followed for naming substituents: 'chloro' comes before 'methyl'.
Therefore,the correct $IUPAC$ name is $1-$chloro$-3-$methylbutane.

(C) Crotonaldehyde has the chemical structure $CH_3-CH=CH-CHO$.
It contains a chain of $4$ carbon atoms with a double bond at the $2^{nd}$ position and an aldehyde group at the $1^{st}$ position.
Therefore,the $IUPAC$ name is $But-2-en-1-al$.

(A) The given compound is $CH_3-CH=C(CH_2-CH_3)-CH_2-CH_2-CH_3$.
First,identify the longest carbon chain containing the double bond.
The longest chain consists of $6$ carbon atoms,so the parent alkane is hexane,and the alkene is hexene.
Number the chain starting from the end that gives the double bond the lowest possible locant.
Numbering from the left,the double bond starts at carbon $2$.
At the $3^{rd}$ carbon atom,there is an ethyl group $(-CH_2-CH_3)$ attached as a substituent.
Combining these,the $IUPAC$ name is $3-$ethyl$-2-$hexene.

(B) $1$. 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.
$3$. The structure is $CH_3-CH(CH(CH_3)_2)-CH_2-CH_2-CH_3$. Expanding the isopropyl group: $CH_3-CH(CH_3)-CH(CH_3)-CH_2-CH_2-CH_3$.
$4$. Numbering from left to right gives methyl groups at positions $2$ and $3$.
$5$. Therefore,the $IUPAC$ name is $2,3-$dimethylhexane.

(B) $1$. Identify the longest carbon chain containing the principal functional group $(-OH)$ and the double bond. The chain has $6$ carbons,so the parent alkane is hexane.
$2$. Number the chain from the end that gives the lowest locants to the functional groups. The $-OH$ group gets priority over the double bond and the chloro substituent.
$3$. Numbering from left to right: $C1$ is the carbon attached to $-OH$ and $-Cl$. Thus,the $-OH$ and $-Cl$ are at position $2$.
$4$. The double bond starts at carbon $5$. Therefore,the name is $2-$chloro$-2-$hydroxyhex$-5-$ene.

(A) $1$. Identify the longest carbon chain containing the functional group ($-OH$ group). The longest chain has $5$ carbon atoms,so the parent alkane is pentane.
$2$. Number the chain from the end that gives the lowest locant to the functional group. Numbering from left to right,the $-OH$ group is at position $2$.
$3$. Identify the substituents: there are two methyl groups $(-CH_3)$ at positions $2$ and $4$.
$4$. Combining these,the name is $2, 4-$dimethylpentan$-2-$ol.