Tag: hydroxy compounds and ethers

Questions Related to hydroxy compounds and ethers

Phenol is a:

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. volatile liquid

  2. non-volatile liquid

  3. volatile solid

  4. non-volatile solid

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Correct Option: C
Explanation:

Phenol is a non-volatile solid. its boiling point is 182 deg C which is high due to intermolecular hydrogen bonding.

Alcohols containing only up to ___________ carbon atoms are completely miscible with water.

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. three

  2. four

  3. five

  4. two

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Correct Option: A
Explanation:

Hydroxyl group makes the alcohol molecule polar and these are used as protic solvents. Two opposing solubility trends in alcohols are the tendency of the polar OH to promote solubility in water and the tendency of the carbon chain to resist it. So, methanol, ethanol, propanol are miscible in water as the OH group overcomes the short carbon chain.

Among the following compounds, the most acidic is:

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. p-nitrophenol

  2. o-hydroxybenzoic acid

  3. p-toluic acid

  4. p-hydroxybenzoic acid

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Correct Option: B
Explanation:

Order of strength is ortho hydroxy benzoic acid > Toulic acid > p-hydroxy benzoic acid > p nitro phenol. Ortho hydroxy acid is strongest acid due to stabilisation conjugate by intermolecular H-bond which outweigh the electron donating resonance effect of –OH

 

In which of the following solvents, KI has highest solubility? The dielectric constant $(\epsilon)$ of each liquid is given in parentheses.

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. $ C _{6}H _{6}(\epsilon =0)$

  2. $(CH _{3}) _{2}CO(\epsilon =21)$

  3. $CH _{3}OH(\epsilon =32)$

  4. $CCl _{4}(\epsilon =0)$

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Correct Option: C
Explanation:

KI is an ionic compound. Hence, it will be most soluble in apolar solvent, which has a high value of dielectric constant. Hence, $CH _3OH$ with the highest value of dielectric constant among the given options will provide high solubility.

Phenol is an organic compound even though it is soluble in water due to the presence of:

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. ionic bonding

  2. covalent bonding

  3. hydrogen bonding

  4. coordinate bonding

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Correct Option: C
Explanation:

Phenol is an organic compound even though it is soluble in water due to the presence of hydrogen bonding. Phenol has hydroxyl group which is involved in the formation of hydrogen bonds with water. It increases the solubility.  Hydrogen bonding is possible when $H$ atom is attached to electronegative $N,\ O$ or $F$ atom.

Tertiary alcohol on treatment with cyanide in presence of conc. ${ H } _{ 2 }{ SO } _{ 4 }$ gives corresponding primary amine. This reaction is called as :

chemistry hydroxy compounds and ethers alcohol nomenclature of alcohols and phenols introduction to alcohols

  1. Schmidt reaction

  2. Curtius degradation

  3. Leuckart reaction

  4. Ritter reaction

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Correct Option: B

In the reaction 2A+B --> 2C + D , 5 mol/lt of 'A; are allowed to react with 3mol/lt of B.After 5 seconds the concentration of A was found to be 4 molar What is the rate of reaction in terms of A>

chemistry hydroxy compounds and ethers alcohol nomenclature of alcohols and phenols introduction to alcohols

  1. 0.1 m/sec

  2. 0.2

  3. 0.3

  4. 0.15

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Correct Option: B

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

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

  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.

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Correct Option: A
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.

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

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

  1. X > Y > Z

  2. Y > X > Z

  3. Z > X > Y

  4. Z > Y > X

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Correct Option: D
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 $Z>Y>X$

The_____ ethers are highly volatile and flammable.

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

  1. higher

  2. lower

  3. both A and B

  4. None of these

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Correct Option: B