Alcohol, Phenol and Ether MCQ Questions & Answers in Organic Chemistry | Chemistry
Learn Alcohol, Phenol and Ether MCQ questions & answers in Organic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
51.
Diethyl ether reacts, inspite of its usual inert nature, with :
A
Dilute suphuric acid
B
Dilute sodium hydroxide
C
Boron trifluoride
D
Metallic sodium
Answer :
Boron trifluoride
Boron trifluoride being a lewis acid forms adduct with diethyl ether which is a lewis base.
52.
What is the major product of the following reaction ?
A
B
C
D
Answer :
53.
In the given reactions,
$$X$$ and $$Y$$ are respectively
A
bromobenzene and acetophenone
B
$$o$$ - and $$p$$ - bromophenol and salicylaldehdye
C
$$p$$ - bromophenol and salicylic acid
D
$$o$$ - bromophenol and benzoic acid
Answer :
$$o$$ - and $$p$$ - bromophenol and salicylaldehdye
54.
$$C{H_3}C{H_2}OH$$ can be converted into $$C{H_3}CHO$$ by
A
catalytic hydrogenation
B
treatment with $$LiAl{H_4}$$
C
treatment with pyridinium chlorochromate
D
treatment with $$KMn{O_4}$$
Answer :
treatment with pyridinium chlorochromate
Pyridinium chlorochromate $$(PCC),$$ a complex of chromium trioxide with pyridine and $$HCl$$ gives good yield of aldehydes and prevents further oxidation to carboxylic acids.
\[C{{H}_{3}}C{{H}_{2}}OH\xrightarrow{PCC}C{{H}_{3}}CHO\]
55.
$$tert$$ - Butyl ethyl ether can’t be prepared by which reaction ?
A
$$tert$$ - Butanol + ethanol \[\xrightarrow{{{H}^{+}}}\]
B
$$tert$$ - Butyl bromide + sodium ethoxide \[\to \]
C
Sodium $$tert$$ - butoxide + ethyl bromide \[\to \]
\[{{\left( C{{H}_{3}} \right)}_{3}}CBr+NaO{{C}_{2}}{{H}_{5}}\] can’t be applied for synthesising the ether because sod. ethoxide, being a strong base, will preferentially cause elimination reaction.
\[{{\left( C{{H}_{3}} \right)}_{3}}CBr\xrightarrow{^{-}O{{C}_{2}}{{H}_{5}}}{{\left( C{{H}_{3}} \right)}_{2}}C=C{{H}_{2}}+HBr\]
In isobutene + ethanol, isobutene will form $$tert$$ - butyl cation which reacts with ethanol, a nucleophile to form ether.
\[{{\left( C{{H}_{3}} \right)}_{2}}C=C{{H}_{2}}\xrightarrow{{{H}^{+}}}{{\left( C{{H}_{3}} \right)}_{2}}\overset{+}{\mathop{C}}\,C{{H}_{3}}\xrightarrow[\left( ii \right)\,-{{H}^{+}}]{\left( i \right)\,C{{H}_{3}}C{{H}_{2}}OH}{{\left( C{{H}_{3}} \right)}_{3}}COC{{H}_{2}}C{{H}_{3}}\]
56.
Among the following ethers which one will produce methyl alcohol on treatment with hot concentrated $$HI?$$
A
B
C
D
Answer :
The ether which gives more stable carbocation, forms $$C{H_3}OH$$ as one of the product with hot $$conc.$$ $$HI.$$ The order of stability of carbocation is
$${3^ \circ } > {2^ \circ } > {1^ \circ }$$
Thus, gives $$C{H_3}OH$$ as one of the product. The reaction proceeds as
57.
Which of the following is not a characteristic of alcohol?
A
They are lighter than water.
B
Their boiling points rise fairly uniformly with rising molecular weight.
C
Lower members are insoluble in water and organic solvents but the solubility regularly increases with molecular mass.
D
Lower members have a pleasant smell and burning taste, higher members are colourless and tasteless.
Answer :
Lower members are insoluble in water and organic solvents but the solubility regularly increases with molecular mass.
No explanation is given for this question. Let's discuss the answer together.
58.
An alcohol $$X$$ on heating with concentrated $${H_2}S{O_4}$$ gives an alkene $$Y$$ which can show geometrical isomerism. The alcohol $$X$$ is
A
$$C{H_3}C{H_2}CH\left( {OH} \right)C{H_3}$$
B
$${\left( {C{H_3}} \right)_2}C\left( {OH} \right)CH{\left( {C{H_3}} \right)_2}$$
C
$${\left( {C{H_3}} \right)_3}C\left( {OH} \right)$$
D
$${\left( {C{H_3}} \right)_2}C\left( {OH} \right)C{H_2}C{H_3}$$
\[\underset{\left( X \right)}{\mathop{C{{H}_{3}}C{{H}_{2}}CH\left( OH \right)C{{H}_{3}}}}\,\] \[\xrightarrow[{{H}_{2}}S{{O}_{4}}]{\text{Conc}\text{.}}\underset{\left( Y \right)}{\mathop{C{{H}_{3}}CH=CHC{{H}_{3}}}}\,\]
59.
Identify $$A, B$$ and $$C.$$
\[A\xrightarrow{C{{H}_{3}}MgBr}B\xrightarrow{{{H}_{3}}{{O}^{+}}}C\]
\[\underset{\left( A \right)}{\mathop{C{{H}_{3}}COC{{H}_{3}}}}\,\xrightarrow{C{{H}_{3}}MgBr}\] \[\underset{\left( B \right)}{\mathop{C{{H}_{3}}\underset{\begin{smallmatrix}
\,| \\
\,\,\,\,C{{H}_{3}}
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,\,\,C{{H}_{3}} \\
\,|
\end{smallmatrix}}{\mathop{-C-}}}\,OMgB}}\,r\xrightarrow{{{H}_{3}}{{O}^{+}}}\] \[\underset{\left( C \right)}{\mathop{C{{H}_{3}}\underset{\begin{smallmatrix}
| \\
\,\,\,\,C{{H}_{3}}
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,\,C{{H}_{3}} \\
|
\end{smallmatrix}}{\mathop{-C-}}}\,OH}}\,\]
60.
Which of the following is the proper method to prepare $$n$$ - hexane from $$n$$ - propyl alcohol?
\[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH\xrightarrow{\left( X \right)}\] \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}Br\xrightarrow{\left( Y \right)}\] \[C{{H}_{3}}{{\left( C{{H}_{2}} \right)}_{4}}C{{H}_{3}}\]
A
$$\left( X \right)\,{\text{ - }}\,HBr{\text{,}}\left( Y \right)\,{\text{ - }}\,HCN$$
B
$$\left( X \right)\,{\text{ - }}\,HBr,\left( Y \right)\,{\text{ - }}\,Na,{\text{ether}}$$
C
$$\left( X \right)\,{\text{ - }}\,B{r_2},\left( Y \right)\,{\text{ - }}\,C{H_3}CN$$
D
$$\left( X \right)\,{\text{ - }}\,B{r_2},\left( Y \right)\,{\text{ - }}\,KMn{O_4}$$
Answer :
$$\left( X \right)\,{\text{ - }}\,HBr,\left( Y \right)\,{\text{ - }}\,Na,{\text{ether}}$$
No explanation is given for this question. Let's discuss the answer together.