Alcohol, Phenol and Ether MCQ Questions & Answers in Organic Chemistry | Chemistry
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91.
What is the product of the following sequence of reactions ?
\[{{\left( C{{H}_{3}} \right)}_{2}}C=CH.C{{H}_{2}}C{{H}_{3}}\] \[\xrightarrow[\left( \text{ii} \right)\,{{H}_{2}}{{O}_{2}},O{{H}^{-}}]{\left( \text{i} \right)\,B{{H}_{3}}/THF}\,\,\xrightarrow[C{{H}_{2}}C{{l}_{2}}]{PCC}\] \[\xrightarrow[\left( \text{ii} \right)\,{{H}_{3}}{{O}^{+}}]{\left( \text{i} \right)\,C{{H}_{3}}MgBr}\]
A
2, 4 - dimethyl - 3 - pentanol
B
2, 3 - dimethyl - 3 - pentanol
C
2, 3 - dimethyl - 2 - pentanol
D
2, 2 - dimethyl - 3 - pentanol
Answer :
2, 3 - dimethyl - 3 - pentanol
92.
Phenol is heated with a solution of mixture of $$KBr$$ and $$KBr{O_3}.$$ The major product obtained in the above reaction is
A
2-bromophenol
B
3-bromophenol
C
4-bromophenol
D
2, 4, 6-tribromophenol
Answer :
2, 4, 6-tribromophenol
$$KB{r_{\left( {aq} \right)}} + KBr{O_{3\left( {aq} \right)}} \to B{r_{2\left( {aq} \right)}}$$
This bromine reacts with phenol and gives 2, 4, 6-tribromophenol.
93.
The product of acid catalyzed hydration of 2 - phenylpropene is
A
3 - phenyl - 2 - propanol
B
1 - phenyl - 2 - propanol
C
2 - phenyl - 2 - propanol
D
2 - phenyl - 1 - propanol
Answer :
2 - phenyl - 2 - propanol
NOTE : Addition of water to 2-phenylpropene follows
Markownikov’s rule.
94.
Which of the following diols would cleave into two fragments with $$HI{O_4}$$
A
1, 3 - hexanediol
B
2, 4 - hexanediol
C
1, 6 - hexanediol
D
3, 4 - hexanediol
Answer :
3, 4 - hexanediol
95.
Which of the following statements is not correctly showing the trend of the properties mentioned?
Solubility of alcohols decreases with increase in size of alkyl group. Boiling points of alcohols increase with increase in the number of carbon atoms and decrease with increase of branching in carbon chain.
Hence, \[C{{H}_{3}}\underset{\begin{smallmatrix}
| \\
\,\,\,C{{H}_{3}}
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,\,\,C{{H}_{3}} \\
|
\end{smallmatrix}}{\mathop{-C-}}}\,OH<\] \[C{{H}_{3}}\underset{\begin{smallmatrix}
|\,\,\,\,\, \\
C{{H}_{3}}\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,C{{H}_{2}}OH\] $$ < C{H_3}C{H_2}C{H_2}C{H_2}OH$$
96.
An ether $$\left( A \right),{C_5}{H_{12}}O,$$ when heated with excess of hot concentrated $$HI$$ produced two alkyl halides which when treated with $$NaOH$$ yielded compounds $$(B)$$ and $$(C).$$ Oxidation of $$(B)$$ and $$(C)$$ gave a propanone and an ethanoic acid
respectively. The $$IUPAC$$ name of the ether $$(A)$$ is :
A
2 - ethoxypropane
B
ethoxypropane
C
methoxybutane
D
2 - methoxybutane
Answer :
2 - ethoxypropane
hence the IUPAC name of compound is
97.
The reaction between phenol and chloroform in the presence of aqueous $$NaOH$$ is
A
nucleophilic substitution reaction
B
electrophilic addition reaction
C
electrophilic substitution reaction
D
nucleophilic addition reaction
Answer :
electrophilic substitution reaction
This reaction is Reimer-Tiemann reaction and it is an electrophilic substitution reaction.
98.
Which reducing agent is used for the following conversion?
$$RCOOH \to RC{H_2}OH$$
99.
Which of the following alcohols is dehydrated most readily with $$conc.\,{H_2}S{O_4}?$$
A
B
C
D
Answer :
The reaction involves the formation of carbocation as intermediate. Hence more the stability of the carbocation, more will be the rate of reaction. Let us draw the structure of the corresponding carbocation and observe the relative stability of the four benzyl carbocations. The relative stability of the four carbocations is
100.
In the following reaction.
\[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}+4H\xrightarrow{\text{Red}\,\,P+HI}2X+{{H}_{2}}O\,;X\] is
A
ethane
B
ethylene
C
butane
D
propane
Answer :
ethane
Ethers are reduced by red $$P$$ and $$HI$$ to alkanes through alkyl iodides \[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}\xrightarrow{\text{red}\,\,P+HI}2{{C}_{2}}{{H}_{5}}I\xrightarrow{\text{red}\,\,P+HI}2{{C}_{2}}{{H}_{6}}\]