Tag: alcohols, phenols and ethers

Questions Related to alcohols, phenols and 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

Show answer
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.

Show answer
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

Show answer
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.

Show answer
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 $D$

An ether is more volatile than alcohol having the same molecular formula. This is due to:

chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

  1. intermolecular hydrogen bonding in ethers

  2. dipolar character of ethers

  3. alcohols having resonance structures

  4. intermolecular hydrogen bonding in alcohols

Show answer
Correct Option: D
Explanation:

An ether which is almost nonpolar is more volatile than alcohol having same molecular formula .this is due to intermolecular hydrogen bonding in alcohols .so alcohols have high bonding point.

An organic compound with molecular formula $C _4H _{10}O$ does not react with sodium . With excess of HI it gives only one type of alkyl halide. The compound is:

chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

  1. $C _2H _5OC _2H _5$

  2. $CH _3{\underset{OCH _3}{\underset{|}{C}}}HCH _3$

  3. $CH _3CH _2CH _2OCH _3$

  4. $CH _3CH _2CH _2CH _2OH$

Show answer
Correct Option: A
Explanation:

$C _4H _{10}O$ can have two structures :


$CH _3CH _2CH _2CH _2OH$   and  $C _2H _5OC _2H _5$.

Since it does not react with Na metal, it can not be an alcohol.

$C _2H _5OC _2H _5 + \underset{excess}HI\rightarrow 2C _2H _5I + H _2O$

Which of the following products are not correctly matched in the given reactions?

chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

  1. $C _2H _5OCH _3 + HBr \xrightarrow{373K} C _2H _5OH + CH _3Br$

  2. $C _2H _5OC _2H _5 + 2HI \rightarrow C _2H5I + C _2H _5OH$

  3. $C _2H _5OC _2H _5 + \overset{Excess}{HCl} \xrightarrow{Cold} [(C _2H _5) _2O^+H]Cl^-$

  4. $(CH _3) _3COC _2H _5 \xrightarrow{HI} (CH _3) _3CI + C _2H _5OH$

Show answer
Correct Option: B
Explanation:

$C _2H _5-O-C _2H _5 +\underset{(excess)} 2HI \rightarrow 2C _2H _5I + H _2O$

Anisole on reaction with chloromethane in presence of anhydrous $AlCl 3$ gives __________.

chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

  1. o-methyl anisole and p-methoxy anisole

  2. p-methyl anisole and p-methoxy anisole

  3. o-methyl anisole and p-methyl anisole

  4. o-methoxy acetphenone and p-methoxy acetophenone .

Show answer
Correct Option: C
Explanation:
Anisole i.e. Phenyl methyl ether $CH _3OC _6H _5$ reaction with Chloromethane in the presence of anhy $AlCl _3$ electrophilic substitution reaction at ortho and para position w.r.t. methoxy group on benzene ring. It is called Friedel-craft alkylation reaction and represented as:
$C _6H _5OCH _3+ CH _3Cl \overset {AlCl _3}{\rightarrow} o-CH _3C _6H _5OCH _3+p-CH _3C _6H _5OCH _3$
Hence Anisole on reaction with chloromethane in presence of anhydrous AlCl3 gives o-methyl anisole and p-methyl anisole

The number of monochloro derivaties of 2-methoxy propane are possible are: 

chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

  1. 2

  2. 1

  3. 3

  4. 4

Show answer
Correct Option: C
Explanation:

$\quad \quad \quad OC{ H } _{ 3 }\ \hspace{2mm} \quad \quad \quad |\ { H } _{ 3 }C-CH-C{ H } _{ 3 }$

2-methoxypropane
The number of monochloro derivatives are 3. They are:
1) $\quad \quad \hspace{2mm} \quad OC{ H } _{ 3 }\ \quad \quad \quad \quad |\ { H } _{ 2 }C-CH-C{ H } _{ 3 }\ \quad |\ \hspace{2mm} Cl$
2) $\quad \quad  \quad OC{ H } _{ 3 }\ \quad \hspace{2mm} \quad \quad |\ { H } _{ 3 }C-C-C{ H } _{ 3 }\ \quad \quad \hspace{2mm} \quad |\ \quad \quad \quad Cl$
3) $\quad \quad  \quad OC{ H } _{ 2 }-Cl\ \quad \hspace{2mm} \quad \quad |\ { H } _{ 3 }C-C-C{ H } _{ 3 } $