Tag: ethers

Quizzes (2) Questions (60)

Questions Related to ethers

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

Oxygen atom of ether is: 

  1. very active

  2. replaceable

  3. active

  4. comparatively inert
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Oxygen atom of ether is comparatively inert.

 $C-O-C$ linkage is quite stable. Under ordinary conditions, ethers are not acted upon by dilute acids, bases and most of the oxidizing and reducing agents. 

Hence correct answer is option D.
Multiple choice chemistry hydroxy compounds and ethers chemical properties of ethers ethers alcohols, phenols and ethers

Diethyl ether can be decomposed with:

  1. $HI$
  2. $KMnO _4$
  3. $NaOH$
  4. $H _2O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On heating with concentrated Hydrogen iodide $(HI)$ the C-O bond in ethers breaks forming alcohol and alkyl iodide. For example,

 ${ C } _{ 2 }{ H } _{ 5 }-O-{ C } _{ 2 }{ H } _{ 5 }+HI\longrightarrow { C } _{ 2 }{ H } _{ 5 }-I+{ C } _{ 2 }{ H } _{ 5 }OH$

 On boiling with excess of concentrated Hydrogen iodide $(HI)$, Alkyl iodide is formed.

${ C } _{ 2 }{ H } _{ 5 }-O-{ C } _{ 2 }{ H } _{ 5 }+2HI\longrightarrow 2{ C } _{ 2 }{ H } _{ 5 }-I+{ H } _{ 2 }O$

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

Ethers are heated with excess of conc. hydrogen halide to give alkyl halide, then the reactivity order of hydrogen halide is :

  1. $HCl < HBr < HF$
  2. $HI > HBr > HCl $
  3. $HF < HCl < HBr $

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When $HX$ is in excess and reaction is carried out at high temperature. Iodine is a good nucleophile, displaces an alcohol molecule by $SN^2$ mechanism thus $HI>HBr>HCl$

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

Ethyl phenyl ether on boiling with conc. HBr gives: 

  1. phenol and ethane

  2. bromobenzene and ethane

  3. phenol and ethyl bromide

  4. bromobenzene and ethanol
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethyl phenyl ether, an alkyl aryl ether, undergoes cleavage upon heating with concentrated HBr to yield phenol and an alkyl halide. Because the oxygen-phenyl bond has partial double bond character due to resonance, cleavage occurs at the alkyl-oxygen bond, producing phenol and ethyl bromide.

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

Ethers have lower boiling points than their corresponding isomeric alcohols because of?

  1. hydrogen bonding in alcohols that is absent in ethers due to low polarity

  2. hydrogen bonding in ethers due to high polarity

  3. insolubility of ethers in water due to less polarity

  4. inertness of ethers as compared to alcohols.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethers ROR cannot form intermolecular Hydrogen bond due to the absence of H attached with the electronegative atom as N/O/F, but in case of alcohols, they have -OH which can undergo intermolecular hydrogen bonding and that increases their boiling point.

Thus, Ethers have lower boiling points than their corresponding isomeric alcohols because of hydrogen bonding in alcohols that is absent in ethers due to low polarity.

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

Correct order of boiling points among following is: $\underset{(X)}{CH _3(CH _2) _3CH _3}, \,\,\,\,\underset{(Y)}{C _2H _5OC _2H _5},\,\,\,\,\,\,\underset{(Z)}{CH _3(CH _2) _3OH}$

  1. X > Y > Z

  2. Y > X > Z

  3. Z > X > Y

  4. Z > Y > X
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The boiling point of a molecule depends on the strength of intermolecular interaction such as Vandewaal's attraction, hydrogen bonding etc.

Alkanes, such as $\underset{X}{CH _3(CH _2) _3CH _3}$, being non-polar have the weakest force of attraction called dispersion or London forces.
Ethers, such as $\underset{(Y)}{C _{2}H _{5}OC _2H _5}$, have small dipole moment or weakly polar thus have dipole-dipole interaction. This is stronger than the London forces.
Alcohols, such as $\underset{(Z)}{CH _3(CH _2) _3OH}$, are polar molecules, therefore, have strong dipolar interaction. Moreover, they form an intermolecular hydrogen bond that further increases the attraction (association).

Hence the order of their boiling point will be:
$\underset{(Z)}{CH _3(CH _2) _3OH}>\underset{(Y)}{C _{2}H _{5}OC _2H _5}>\underset{X}{CH _3(CH _2) _3CH _3}$

OR $Z>Y>X$