(a) Classify the following as primary/secondary/tertiary alcohols: $CH_3 ext{--}CH_2 ext{--}CH_2 ext{--OH}$ , and a benzene ring with a -CH2-CH(OH)-CH3 substituent. (b) Predict the products of the following reactions: (i) $CH_3 ext{--}CH_2 ext{--}CH_2 ext{--O--}CH_3 + HBr \

Question

(a) Classify the following as primary/secondary/tertiary alcohols: $CH_3	ext{--}CH_2	ext{--}CH_2	ext{--OH}$ , and a benzene ring with a -CH2-CH(OH)-CH3 substituent. (b) Predict the products of the following reactions: (i) $CH_3	ext{--}CH_2	ext{--}CH_2	ext{--O--}CH_3 + HBr \xrightarrow{373\ K}$ ? (ii) phenetole (benzene ring--$OC_2H_5$) $\xrightarrow[	ext{conc. } HNO_3]{	ext{conc. } H_2SO_4}$ ? (c) Give the structure of the products you would expect when Butan-1-ol reacts with the following: (i) $SOCl_2$ (ii) $HCl	ext{--}ZnCl_2$

**OR**

(d) Identify the products A, B, C and D from the following reactions: (i) chlorobenzene (benzene ring--Cl) $\xrightarrow[300\ atm]{	ext{NaOH, HCl, }623\ K} A \xrightarrow[\Delta]{	ext{Zn-dust}} B$ (ii) $CH_3CHO \xrightarrow[(ii)\ H_2O/H^{+}]{(i)\ CH_3MgBr} C \xrightarrow[443\ K]{H_2SO_4} D + H_2O$ (e) Convert cumene to phenol. (f) Give the structures and IUPAC names of the products expected from the following reactions: (i) Catalytic reduction of butanal (ii) Hydration of propene in the presence of dilute sulphuric acid.

Accepted Answer

>

> [!TLDR]
> This question runs through alcohol/ether/phenol classification, ether cleavage, phenol nitration, and alcohol-to-halide conversions (primary branch), or the industrial phenol-from-cumene route together with a chlorobenzene-to-phenol-to-benzene sequence and a Grignard-then-dehydration sequence (alternative branch).
>
> **(a) Classification of alcohols:**
>
> - $CH_3	ext{--}CH_2	ext{--}CH_2	ext{--OH}$ (propan-1-ol): the carbon bearing $-OH$ is attached to only one other carbon $\Rightarrow$ **primary (1°) alcohol**.
> - Benzene ring—$CH_2	ext{--}CH(OH)	ext{--}CH_3$ (1-phenylpropan-2-ol): the carbon bearing $-OH$ is attached to two other carbons (the benzylic $CH_2$ and the terminal $CH_3$) $\Rightarrow$ **secondary (2°) alcohol**.
>
> **(b)(i) Ether cleavage: $CH_3CH_2CH_2	ext{--O--}CH_3 + HBr$ (373 K):**
>
> On protonation of the ether oxygen, $Br^-$ attacks the less hindered (here, methyl) carbon by an $S_N2$ pathway, cleaving the C–O bond at the smaller alkyl group:
> $$CH_3CH_2CH_2	ext{--O--}CH_3 + HBr ightarrow CH_3CH_2CH_2OH + CH_3Br$$
> With excess hot HBr, the resulting propan-1-ol is itself further converted to 1-bromopropane:
> $$CH_3CH_2CH_2OH + HBr ightarrow CH_3CH_2CH_2Br + H_2O$$
>
> **(b)(ii) Nitration of phenetole:**
>
> The $-OC_2H_5$ group is strongly activating and ortho/para-directing, so nitration gives a mixture of ortho- and para-nitrophenetole (predominantly para):
> $$C_6H_5	ext{--}OC_2H_5 \xrightarrow[	ext{conc. }H_2SO_4]{	ext{conc. }HNO_3} o	ext{-} \& p	ext{-O}_2N	ext{--}C_6H_4	ext{--}OC_2H_5 + H_2O$$
>
> **(c) Butan-1-ol reactions:**
>
> (i) With $SOCl_2$ (best method — clean, only gaseous by-products):
> $$CH_3CH_2CH_2CH_2OH + SOCl_2 ightarrow CH_3CH_2CH_2CH_2Cl + SO_2\uparrow + HCl\uparrow$$
>
> (ii) With Lucas reagent (conc. $HCl$ + anhydrous $ZnCl_2$): primary alcohols react only slowly (requiring heating), via an $S_N2$-type displacement:
> $$CH_3CH_2CH_2CH_2OH + HCl \xrightarrow{ZnCl_2,\ \Delta} CH_

Q.(a) Classify the following as primary/secondary/tertiary alcohols: $CH_3\text{--}CH_2\text{--}CH_2\text{--OH}$ , and a benzene ring with a -CH2-CH(OH)-CH3 substituent.

Concept understanding — Lucas Test

The Lucas Test: Why Some Alcohols React in Seconds and Others Take Days

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Carbocation Stability: The Deciding Factor

The Precise Statement

How to Perform and Interpret

Q.(a) Classify the following as primary/secondary/tertiary alcohols: CH3–CH2–CH2–OHCH_3\text{--}CH_2\text{--}CH_2\text{--OH}CH3​–CH2​–CH2​–OH , and a benzene ring with a -CH2-CH(OH)-CH3 substituent.

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Q.(a) Classify the following as primary/secondary/tertiary alcohols: $CH_3\text{--}CH_2\text{--}CH_2\text{--OH}$ , and a benzene ring with a -CH2-CH(OH)-CH3 substituent.

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