Tag: physical properties of alcohols and phenols

Questions Related to physical properties of alcohols and phenols

Melting point of phenol 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. $53^0C$

  2. $43^0C$

  3. $33^0C$

  4. $23^0C$

Show answer
Correct Option: B
Explanation:

Pure phenols are generally colorless solids or liquids. Phenols (molecular weight $=94$) have the relatively low melting point. So generally exist in liquid form above room temperature.

its melting point is $43^0C$.

Which of the following is not true regarding phenol?

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. Pure phenol is a white crystalline solid

  2. Phenol smell as disinfectant.

  3. It causes immediate white blistering to the skin

  4. None of these

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Correct Option: D
Explanation:

Pure Phenols are colorless solids or liquids. These are used as disinfectant due to their chemical properties. Also, because of its acidic nature, it causes immediate white blistering to the skin. 

Molecular weight of phenol 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. $94.11$

  2. $104.11$

  3. $86.11$

  4. $98$

Show answer
Correct Option: A
Explanation:
Molecular formula of Phenol is $C _6H _5-OH$
Therefore, moelcular weight: $6 (Mass \ of \ Carbon) + 6 (Mass \ of \ Hydrogen)+16 (Mass \ of \ Oxygen)$
$=6 \times 12 + 5 \times 1 + 16 \times 1 + 1 \times 1$
$=94.11$

The major product of Raschig process was taken for litmus test.It was observed that it turned:

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. red litmus blue

  2. blue litmus red

  3. no change in colour

  4. very slight change in colour from red towards blue

Show answer
Correct Option: B
Explanation:

Phenol is obtained as the major product of Raschig process.Phenol is mildly acidic in nature so it turns blue litmus red.

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

Show answer
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

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

Show answer
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

Show answer
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.