Alcohols and Ethers - Result Question 32
####35. Statement I Solubility of $n$-alcohol in water decreases with increase in molecular weight.
Statement II The relative proportion of the hydrocarbon part in alcohols increases with increasing molecular weight which permit enhanced hydrogen bonding with water.
$(1988,2 M)$
Passage Based Questions
Passage 1
A tertiary alcohol $H$ upon acid catalysed dehydration gives a product $I$. Ozonolysis of $I$ leads to compounds $J$ and $K$.
Compound $J$ upon reaction with $KOH$ gives benzyl alcohol and a compound $L$, whereas $K$ on reaction with $KOH$ gives only $M$.
$(2008,3 \times 4 M=12 M)$
Show Answer
Answer:
Correct Answer: 35. secondary
Solution:
- $R-OH \leftarrow$ Hydrophilic
Hydrophobic
Increasing molecular weight increases hydrocarbon $(R)$ proportion that lowers the solubility in water.
Passage 1
Compound $J$ must be benzaldehyde because it on treatment with $KOH$ undergoing Cannizzaro’s reaction producing benzyl alcohol and pot-benzoate $(L)$.
$C _6 H _5-CHO \xrightarrow{KOH} \underset{\text { benzyl alcohol }}{C _6 H _5-CH _2 OH}+C _6 H _5 COOK(L)$
Also $M$ is aldol condensation product formed from acetophenone
acetophenone $(K)$
$\Rightarrow I=\underset{H _3 C}{Ph} \succ C=CH-Ph$
and $H=Ph \underset{\substack{CH _3 \ 3^{\circ} \text {-alcohol }}}{\stackrel{O}{\mid} \mid}-CH _2-Ph$
