Alkanols are the derivatives of alkanes which are derived by the replacement of $$-H$$ of alkanes with $$-OH$$ (hydroxyl groups).
\[\underset{\text{Alkanes}}{\mathop{{{C}_{n}}{{H}_{2n+2}}}}\,\xrightarrow[+OH]{-H}\underset{\text{Alkanols}}{\mathop{{{C}_{n}}{{H}_{2n+1}}}}\,OH\,\,\text{or}\,\,{{C}_{n}}{{H}_{2n+2}}O\]
223.
Which of the following has lowest boiling point ?
Reactions of alcohols involving cleavage of $$C - OH$$ bond follow the reactivity order :
Tertiary > secondary > primary, according to the stability of carbocation intermediate.
226.
One mole of ethyl acetate on treatment with an excess of $$LiAl{H_4}$$ in dry ether and subsequent acidification produces
A
$$1\,mol$$ acetic acid $$ +\, \,1\,mol$$ ethyl alcohol
B
$$1\,mol$$ ethyl alcohol $$ + \,\,1\,mol$$ methyl alcohol
Phenol on reaction with conc. $${{\text{H}}_2}S{O_4}$$ gives a mixture of $${\text{o - }}$$ and $$p{\text{ - }}$$ products ( i.e., $$ - S{O_3}H$$ group, occupies $${\text{o - ,}}$$ $$p{\text{ - }}$$ position ). At room temperature $${\text{o - }}$$ product is more stable, which on treatment with conc. $$HN{O_3}$$ will yield $${\text{o - }}$$ nitrophenol.
At room temperature $$o-$$ product is more stable
Hence (B) is the correct answer.
228.
The $$C-O-H$$ bond angle in alcohols is slightly less than the tetrahedral angle whereas the $$C-O-C$$ bond angle in ether is slightly greater because
A
of repulsion between the two bulky $$R$$ groups.
B
$$O$$ atom in both alcohols and ethers is $$s{p^3}$$ - hybridised.
C
lone pair - lone pair repulsion is greater than bond pair - bond pair repulsion.
D
None of these.
Answer :
of repulsion between the two bulky $$R$$ groups.