Tag: hydroxy compounds and ethers

Questions Related to hydroxy compounds and ethers

The compound which has the lowest boiling point is: 

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

  1. $H _2O $

  2. $C _2H _5OH$

  3. $CH _3OH $

  4. $C _2H _5OC _2H _5$

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Correct Option: D

The compound which has highest boiling point among the following is: 

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

  1. diethyl ether

  2. ethanol

  3. methanol

  4. water

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Correct Option: D
Explanation:

Boiling point of Diethyl ether $=34.6^0C$


Boiling point of Ethanol $=78.5^0C$

Boiling point of Methanol $=64.7^0C$

Boiling point of Water $=100^0C$

Hydrogen bonding in water and alcohol due to which they have higher boiling points.

Here, water has the highest boiling point among others.

 So correct answer is option D.

The high boiling point of ethanol $(78.2^o C)$ compared to dimethyl ether $(-23.6^o C)$, though both having the same molecular formula $\displaystyle { C } _{ 2 }{ H } _{ 6 }O$, is due to:

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

  1. hydrogen bonding

  2. ionic bonding

  3. co-ordinate covalent bonding

  4. resonance

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Correct Option: A
Explanation:

The high boiling point of ethanol $(78.2 ^oC)$ compared to dimethyl ether $(-23.6^oC)$, though both having the same molecular formula $C _2H _6O$, is due to Hydrogen bonding.
Hydrogen bonding is observed when H atom is attached to more electronegative N, F or O atom.
Ethanol molecules are associated due to hydrogen bonding. This results in higher boiling point.
However, hydrogen bonding is not possible in dimethyl ether.

Maximum boiling point would be shown by:

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

  1. $\displaystyle { CH } _{ 3 }-O-{ CH } _{ 3 }$

  2. $\displaystyle { C } _{ 2 }{ H } _{ 5 }-O-{ C } _{ 2 }{ H } _{ 5 }$

  3. $\displaystyle { CH } _{ 3 }-{ CH } _{ 2 }-{ CH } _{ 2 }-OH$

  4. $\displaystyle ({ CH } _{ 3 }{ ) } _{ 2 }CH-OH$

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Correct Option: C
Explanation:

Maximum boiling point would be shown by n propanol, $\displaystyle { CH } _{ 3 }-{ CH } _{ 2 }-{ CH } _{ 2 }-OH$.
In n-propanol, the molecules are associated due to hydrogen bonding. Hence, the boiling point is higher.
In dimethyl ether and diethyl ether, the boiling point is lower as hydrogen bonding is not possible.
The extent of the hydrogen bonding in isopropanol is lower than that in n-propanol due to +I effect of two methyl groups.
Also, as the degree of branching increases, the boiling point decreases.

The compound which has the lowest boiling point is:

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

  1. $H _{2}O$

  2. $C _{2}H _{5}OH$

  3. $CH _{3}OH$

  4. $CH _{3}OCH _{3}$

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Correct Option: D
Explanation:

D
Due to less chance of hydrogen bonding less association so low boiling point

Among ethanol, dimethyl ether, methanol and propanal, the isomers are

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

  1. ethanol, dimethyl ether, methanol and propanal

  2. ethanol and methanol

  3. ethanol, dimethyl ether, and methanol

  4. ethanol and dimethyl ether

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Correct Option: D
Explanation:

Ethanol $(C _2H _5OH)$ and dimethyl ether $(CH _3-O-CH _3)$ have same molecular formula but different functional groups, so they are isomers.

With ethoxyethane which compound is miscible to almost the same extent?

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

  1. Formaldehyde

  2. Bhutanone

  3. Butan-1-ol

  4. Propan-1-ol

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Correct Option: C
Explanation:

The correct option is $C$. Ethoxyethane is an ether group which is miscible to the alcohol that is Butan $-1-$ol. This is because they have the same molecular mass. 

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

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

  1. dipolar character of ethers

  2. alcohols having resonance structures

  3. inter-molecular hydrogen bonding in ethers

  4. inter-molecular hydrogen bonding in alcohols

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Correct Option: D
Explanation:

An ether is more volatile than an alcohol having the same molecular formula. This is due to intermolecular hydrogen bonding in alcohols. In alcohols, $H$ atom is attached to electronegative $O$ atom. Due to this, $H$ atom of $-OH$ group of one alcohol molecule forms a hydrogen bond with $O$ atom of $-OH$ group of the second alcohol molecule. This results in the intermolecular association. It increases the boiling point and decreases the volatility of alcohol. Such inter-molecular hydrogen bonding is not possible in others as in ethers, H atom is not attached to an electronegative $O$ atom.

The miscibility of ether with _______ resembles those of alcohol of the same molecular mass.

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

  1. methanol

  2. water

  3. DCM

  4. benzene

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Correct Option: B
Explanation:

The miscibility of ether with water resembles those of alcohol of the same moleculer mass. It is generally due to the hydrogen bonding with water in alcohol. So the correct option is $B$.

In iodine charge transfer test the color of ether compound formed is:

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

  1. blue

  2. pale yello

  3. brown

  4. dark red

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Correct Option: C
Explanation:
The correct option is $C$. Ether forms charge transfer complexes with Iodine to give a brown solution.
$R-O-R'\longrightarrow R'I-+RI+H _2O$