Tag: nomenclature of ethers

Questions Related to nomenclature of ethers

In ethers the numbering of the parent chain is done in a way:

nomenclature of ethers alcohols, phenols and ethers chemistry

  1. that the carbon atom linked to the -O-atom gets the lowest number.

  2. that the carbon atom linked to the -O-atom gets the highest number.

  3. that the carbon atom which comes from parental hydrocarbon linked to the -O-atom gets the lowest number

  4. none of these

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Correct Option: A
Explanation:

While doing the numbering of longest parent chain in the ether, it is ensured that the carbon atom linked to the $-O-$ atom gets the lowest number, according to IUPAC nomenclature.

Which of the following statement is not correct in the naming of ethers according to IUPAC rules?

nomenclature of ethers alcohols, phenols and ethers chemistry

  1. Ethers are named as alkoxy alkanes

  2. The numbering of the parent chain is done in such a way so that the carbon atom linked to the -O-atom gets the lowest number.

  3. The two alkyl groups attached to the oxygen are put in alphabetical order

  4. In the case of simple ethers, the prefix tri is attached before the name of the alkyl group.

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Correct Option: D
Explanation:
If both the alkyl groups attached to the $-O-$ atoms are same, then the prefix 'di' is added before the alkyl group. 
Example: $CH _3-O-CH _3$ is named as dimethyl ether.

Which of the following naming is not given correctly?

nomenclature of ethers alcohols, phenols and ethers chemistry

  1. $C _2H _5 - O - C _2H _5$ is Diethyl ether

  2. $C _6H _5 - O - C _6H _5$ is Diphenyl ether

  3. $C _2H _5 - O - C _6H _5$ is Ethyl phenyl ether

  4. $C _2H _5 - O - C _3H _7$ is Diethyl propylether

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Correct Option: D
Explanation:

$C _2H _5$ is ethyl and $C _3H _7$ is propyl. Therefore, the correct common name, arranged in alphabetical order will be Ethyl Propyl Ether.

IUPAC name of the compound $CH _3-\underset{\displaystyle CH _3}{\underset{|}CH}-OCH _3$ is:

nomenclature of ethers alcohols, phenols and ethers chemistry

  1. 1 - methoxy - 1 - methylethane

  2. 2 - methoxy - 2 - methylethane

  3. 2 - methoxypropane

  4. isopropylmethyl ether.

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Correct Option: C
Explanation:

Given molecule: $CH _3-\underset{\displaystyle CH _3}{\underset{|}CH}-OCH _3$

It is an ether $ROR'$. In naming ether, smaller alkyl group among R and R' is treated as side group as alkoxy and the other as alkane along with the position of the alkoxy group. Thus in the given molecule, it is methoxy group at second position of propane (alkane)
$\overset { 1 }{ C } H _{ 3 }-\underset { \overset { 3 }{ C } H _{ 3 } }{ \underset { | }{ \overset { 2 }{ C }  }  }H -OCH _{ 3 }$
Thus its name is: 2-methoxypropane.

Find out the statement which is not correct in the naming of cyclic ethers.

nomenclature of ethers alcohols, phenols and ethers chemistry

  1. If a substituent is an alcohol, the alcohol has higher priority

  2. If a substituent is a halide, ether has higher priority

  3. If both an alcohol group and a halide are present, alcohol has higher priority

  4. If a substituent is an alcohol, the ether has higher priority

Show answer
Correct Option: D
Explanation:

In IUPAC naming of cyclic ethers, if a substituent is an alcohol, the alcohol is given the higher priority over the ether.


Hence, the correct option is $D$