Alcohol and phenols are hydroxy derivatives of hydrocarbons. Both have the tendency to form…
Chemistry20253 marksCase based
Alcohol and phenols are hydroxy derivatives of hydrocarbons. Both have the tendency to form intermolecular hydrogen bonding. Thus, they have higher boiling point and high solubility in water. As the O-H bond is polar in nature they also exhibit acidic property. Acidic characteristic depends upon inductive effect and resonance stabilization. The position and nature of substituents also affects the acidic strength.
(a)[1.0]
Select from each pair as per the property mentioned in the bracket:
(i) Ethanol, Methanol (most acidic)
(ii) O-cresol and m-cresol (least acidic)
(b)[1.0]
Correct the given statement and give a reason for your answer:
'The solubility of phenol is higher than alcohol.'
(c)[1.0]
Compounds [X] and [Y] are functional isomers of each other with molecular formula $\text{C}_3\text{H}_8\text{O}$.
(i) Draw the isomers.
(ii) Which compound will have a lower boiling point and why?
Answer
Answer (a)
Official answer key
(i) Methanol
(ii) o-cresol
Answer (b)
Official answer key
The solubility of phenol is lower than alcohol. The phenyl group being more hydrophobic in nature, the tendency to form intermolecular hydrogen bonding decreases.
Answer (c)
Official answer key
propan-1-ol:
methoxyethane:
(i) X = $\mathrm{CH_3CH_2CH_2OH}$; Y = $\mathrm{CH_3CH_2OCH_3}$
(ii) Compound [Y] will have lower boiling point as it is an ether which cannot form associated molecules by intermolecular hydrogen bond.