281. Which of the following undergoes nucleophilic substitution exclusively by $${S_N}1$$ mechanism?
A
Benzyl chloride
B
Ethyl chloride
C
Chlorobenzene
D
Isopropyl chloride
Answer :
Benzyl chloride
282. $$p$$ - Cresol reacts with chloroform in alkaline medium to give the compound $$A$$ which adds hydrogen cyanide to form the compound $$B.$$ The latter on acidic hydrolysis gives chiral carboxylic acid. The structure of the carboxylic acid is
A
B
C
D
Answer :
283. Among the following sets of reactants which one produces anisole?
A
$$C{H_3}CHO,RMgX$$
B
$${C_6}{H_5}OH,NaOH,C{H_3}l$$
C
$${C_6}{H_5}OH,\,{\text{neutral }}FeC{l_3}$$
D
$${C_6}{H_5} - C{H_3},C{H_3}COCl,AlC{l_3}$$
Answer :
$${C_6}{H_5}OH,NaOH,C{H_3}l$$
284. When phenol is treated with excess bromine water, it gives :
A
$$m $$ - Bromophenol
B
$$o $$ - and $$p $$ - Bromophenol
C
2, 4 - Dibromophenol
D
2, 4, 6 - Tribromophenol
Answer :
2, 4, 6 - Tribromophenol
285.
In the following reactions,
the major products $$A$$ and $$C$$ are respectively
A
B
C
D
Answer :
286.
In the reaction 
the products are
A
B
C
D
Answer :
287.
Which of the following reagents would carry out the following transformation ? $$\left( {D = {}^2H} \right)$$
A
$$NaB{D_4}\,\,{\text{in}}\,\,C{H_3}OH$$
B
$$LiAl{H_4},{\text{then}}\,\,{D_2}O$$
C
$$NaB{D_4}\,\,{\text{in}}\,\,C{H_3}OD$$
D
$$LiAl{D_4},{\text{then}}\,\,{D_2}O$$
Answer :
$$NaB{D_4}\,\,{\text{in}}\,\,C{H_3}OH$$
288. Which of the following alcohols reacts most readily with Lucas reagent?
A
\[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH\]
B
\[C{{H}_{3}}\underset{\begin{smallmatrix}
|\,\,\,\,\, \\
OH\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,C{{H}_{3}}\]
C
\[C{{H}_{3}}\underset{\begin{smallmatrix}
| \\
\,\,\,C{{H}_{3}}
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,\,\,C{{H}_{3}} \\
|
\end{smallmatrix}}{\mathop{-C-}}}\,OH\]
D
\[C{{H}_{3}}\underset{\begin{smallmatrix}
|\,\,\,\,\, \\
C{{H}_{3}}\,
\end{smallmatrix}}{\mathop{-CH-}}\,C{{H}_{2}}OH\]
Answer :
\[C{{H}_{3}}\underset{\begin{smallmatrix}
| \\
\,\,\,C{{H}_{3}}
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,\,\,C{{H}_{3}} \\
|
\end{smallmatrix}}{\mathop{-C-}}}\,OH\]
289. $$HBr$$ reacts fastest with
A
2-methyl propan-1-$$ol$$
B
2-methyl propan-2-$$ol$$
C
propan-2-$$ol$$
D
propan-1-$$ol$$
Answer :
2-methyl propan-2-$$ol$$
